The image of the visible part of the surface of an object facing the observer is called view.
GOST 2.305-68 establishes the following name main views obtained on the main projection planes (see Fig. 165): 7 - front view ( main view); 2 - top view; 3 - left view;
4 - right view; 5 - bottom view; b- back view. In practice, three types are more widely used: front view, top view and left view.
The main views are usually located in a projection relationship with each other. In this case, there is no need to write the name of the views on the drawing.
If any view is displaced relative to the main image, its projection connection with the main view is broken, then an inscription of type “A” is made over this view (Fig. 166).
Rice. 166
Rice. 167
Rice. 168
The direction of view should be indicated by an arrow, indicated by the same capital letter of the Russian alphabet as in the inscription above the view. The ratio of the sizes of the arrows indicating the direction of view should correspond to those shown in Fig. 167.
If the views are in projection connection with each other, but are separated by any images or are not located on the same sheet, then an “A” type inscription is also made above them.
An additional view is obtained by projecting an object or part of it onto an additional projection plane that is not parallel to the main planes (Fig. 168). Such an image must be performed in the case when any part of the object is not depicted without distortion of shape or size on the main projection planes. In this case, the additional projection plane can be located perpendicular to one of the main projection planes.
When an additional view is located in direct projection connection with the corresponding main view, it does not need to be designated (Fig. 168, A). In other cases, the additional view should be marked on the drawing with an inscription of type “A” (Fig. 168, b), and the saint
Rice. 169
When combined with an additional view of the image, you need to put an arrow indicating the direction of view, with the corresponding letter designation.
The secondary view can be rotated while maintaining the same position as the item in the main image. In this case, you need to add a sign to the inscription (Fig. 168, c).
A local view is an image of a separate, limited area of the surface of an object (Fig. 169).
If a local view is located in direct projection connection with the corresponding images, then it is not designated. In other cases, local species are designated similarly to additional species; the local species may be limited by the cliff line (“B” in Fig. 169).
§ 81. Construction of the third type of object from two data
First of all, you need to find out the shape of individual parts of the surface of the depicted object. To do this, both given images must be viewed simultaneously. It is useful to keep in mind which surfaces correspond to the most common images: triangle, quadrilateral, circle, hexagon, etc.
In the top view, they can appear in the shape of a triangle (Fig. 170, A): triangular prism 1, triangular 2 and quadrangular 3 pyramids, cone of rotation 4.
Rice. 170
An image in the form of a quadrangle (square) can be shown in the top view (Fig. 170, b): rotation cylinder 6, triangular prism8, quadrangular prisms 7 And 10, a also other objects bounded by planes or cylindrical surfaces 9.
The shape of a circle can be seen from above (Fig. 170, c): ball 11, cone 12 and cylinder 13 rotation, other surfaces of rotation 14.
The top view in the shape of a regular hexagon has a regular hexagonal prism (Fig. 170, d), limiting the surfaces of nuts, bolts and other parts.
Having determined the shape of individual parts of the surface of an object, you need to mentally imagine their image on the left and the entire object as a whole.
To construct the third type, it is necessary to determine which lines of the drawing should be taken as the basic ones for reporting the dimensions of the image of the object. As such lines, axial lines are usually used (projections of the planes of symmetry of an object and projections of the planes of the bases of an object). Let's look at the construction of the left view using an example (Fig. 171): based on the data from the main view and the top view, construct a left view of the depicted object.
By comparing both images, we establish that the surface of the object includes surfaces: regular hexagonal 1 and quadrangular 2 prisms, two cylinders 3 And 4 rotation and truncated cone 5 of rotation. The object has a frontal plane of symmetry Ф, which is convenient to take as the basis for reporting the dimensions along the width of individual parts of the object when constructing its left view. The heights of individual sections of an object are measured from the lower base of the object and are controlled by horizontal communication lines.
The shape of many objects is complicated by various cuts, cuts, intersections
Rice. 171
Rice. 172
placing surfaces. Then you first need to determine the shape of the intersection lines, and you need to build them at individual points, entering designations for the projections of points, which after completing the construction can be removed from the drawing.
In Fig. 172 shows a left view of an object, the surface of which is formed by the surface of a vertical cylinder of rotation, with a T-shaped cutout in its upper part and a cylindrical hole with a frontally projecting surface. The plane of the lower base and the frontal plane of symmetry F are taken as the base planes. The image of the L-shaped cutout in the left view is constructed using the cutout contour points A B, C, D And E, and the line of intersection of cylindrical surfaces - using points K, L, M and them symmetrical. When constructing the third type, the symmetry of the object relative to the plane F was taken into account.
Lecture 2. PROJECTION DRAWING
2.1. General provisions.
2.3. Sections.
2.4. Cuts.
2.5. Constructing the third projection of a part using two data.
2.6. Control questions.
General provisions
When making technical drawings, various projection images are used, mainly rectangular (orthogonal) projections of the object. Any technical detail or structure is a complex of geometric bodies. When drawing up a drawing and reading it, you must be able to find these components of the geometric shape, as well as build sections, sections, intersection lines, etc.
The drawing must give a complete picture of the shape of the depicted object, its structure, the material from which it is made, and contain information about the methods of its manufacture. At the same time, the drawing of the item must be concise; it must contain a minimum number of images sufficient to read the drawing, manufacture the item based on it, and control it.
For better understanding and reading, drawings should be drawn up according to general rules. All requirements for the design of drawings must be uniform. Therefore, when drawing up drawings, it is necessary to be guided by the basic rules and provisions of GOST, given in section. 1.
The images in the drawings, depending on their content, are divided into types, sections, sections. The rules for depicting objects are established by GOST 2.305-68.
The arrangement of images on drawings in different countries is carried out according to one of two systems - European (symbol of system E) or American (symbol of system A). In our country and in most European countries, the European system for arranging images has been adopted.
Images of objects should be made using the rectangular projection method. In this case, the object is placed between the observer and the corresponding projection planes (Fig. 11). The main projection planes are the six faces of the cube within which the object is located. Faces 1, 2 and 3 correspond to the frontal, horizontal and profile planes of projections. Such projections are called orthogonal projections.
The faces of the cube with the images obtained on them are combined with the plane of the drawing (Fig. 12). In this case, face 6 can be placed next to face 4. The image on the frontal plane of projections is considered the main one.
The object is positioned relative to the frontal plane of projections so that the image on it gives a complete picture of the shape and size of the object and carries the most information about it.
The number of images - views, sections, sections - should be minimal, but sufficient to fully display the item when using the symbols, signs and inscriptions established in the relevant standards.
Kinds
A view is an image facing the observer with the visible part of the surface of an object. To reduce the number of images, it is allowed to show the necessary invisible parts of the object in views using dashed lines.
GOST 2.305-68 establishes the following names of the main views obtained on the main projection planes, see Fig. 11 and 12):
1 – front view or main view(on the frontal plane of projections);
2 – view from above(on the horizontal plane of projections);
3 – left view(on the profile plane of projections);
4 – right view(on the plane opposite to the profile plane of projections);
5 – bottom view(on the plane opposite to the horizontal plane of projections);
6 – back view(on the plane opposite to the frontal plane of projections).
With this arrangement of views, the projections of each point of the depicted object are placed on different types not arbitrarily, but in accordance with the rules of descriptive geometry and lie on general straight lines; Moreover, the projections of any point located on the main view, views on the right, left and behind are located on a common horizontal line, while the projections located on the main view, views from above and below are located on a common vertical line. Thus, the main types are in a projection relationship with each other. In this case, there is no need to sign the name of the views on the drawing.
In order to more rationally use the drawing field, GOST allows views to be placed anywhere in the drawing, outside the projection connection. So, for example, in Fig. 13 the bottom view is shown outside the projection connection with the main view. In this case, the direction of view is indicated by an arrow near the corresponding image, and the same capital letter of the Russian alphabet is written near the arrow and above the view.
If any part of an object cannot be shown in the main views without distorting its shape and size, then additional views are used, obtained on planes not parallel to the main projection planes (Fig. 14). An additional view is marked in the drawing with a capital letter, and an arrow is placed next to the image of the object associated with the additional view, indicating the direction of view with the corresponding letter designation.
If an additional view is located in direct projection connection with the corresponding image, the arrow and the view designation are not applied.
The additional view can be rotated, but, as a rule, maintaining the position adopted for this item in the main image. In this case, the type designation must be supplemented with a graphic image (Fig. 15).
There are cases when it is necessary to clarify only part of the shape of an object; in these cases, a local view is used, which is an image of a separate, limited area of the surface of the object
(Fig. 16).
The detail view is limited to the cliff line or not limited if this does not affect the clarity of the drawing.
If the local view is performed in projection connection with the main view, the direction of view is not indicated, and its designation is not applied. If the projection connection is disrupted, the local view is marked like an additional view.
Sections
Section is the image of a figure resulting from the mental dissection of an object by one or more planes. The section shows only what is obtained directly in the cutting plane. Oblique sections should be avoided by choosing cutting plane directions that produce normal cross sections.
Depending on their location in the drawing, sections that are not part of the section are divided into superimposed ( rice. 17a) and issued(Fig. 17b).
Preference is given to extended sections; Superimposed sections are permitted, but not recommended.
The contour of the extended section is depicted with solid main lines (see Fig. 55b), and the contour of the superimposed section is depicted with solid thin lines (see Fig. 55a), and the contour of the image at the location of the superimposed section is not interrupted. In addition, sections can be located in the gap between parts of the same type (Fig. 18).
The axis of symmetry of the extended or superimposed section is indicated by a thin dash-dotted line. The superimposed section is not indicated by letters.
An extended symmetrical section, the axis of symmetry of which is located on the continuation of the projection of the cutting plane (Fig. 19), and a symmetrical section located in the gap between parts of the same type (see Fig. 18), are not designated or labeled.
For asymmetrical sections located in the gap between parts of the same type (Fig. 20a) or superimposed (Fig. 20b), the section line is supplemented with arrows, but is not marked with letters.
In all other cases, an open line is used for the section line with arrows indicating the direction of view and is designated by the same capital letters of the Russian alphabet, and the section itself is accompanied by an inscription according to type A-A(Fig. 21), i.e. like a cut.
The section in construction and location must correspond to the direction indicated by the arrows.
It is allowed to place the section anywhere in the drawing field (see Fig. 21), as well as with a rotation (Fig. 23), adding the corresponding graphic symbol.
If the secant plane passes through the axis of the surface of rotation that bounds the hole or recess, then the contour of the hole or recess in the section is shown in full (Fig. 22).
In the case when the cutting plane passes through a non-circular hole and the section turns out to consist of separate independent parts, a cut should be used (Fig. 23).
All sections, including those included in the sections, in the drawing details are hatched, and at the same angle, in one direction and with the same distance between the strokes.
Hatch lines make an angle of 45° with the center lines or with the main contour lines of the drawing
The thickness of the hatch lines should be 3 times thinner than the lines of the visible contour. The shaded section should not be conspicuous due to the excessive thickness of the hatching lines or their density.
Cuts
By cut An image of an object mentally dissected by one or more planes is called, while the mental dissection of an object relates only to this section and does not entail changes in other images of the same object. The section (Fig. 24) shows what is obtained in the cutting plane and what is located behind it.
The position of the cutting plane is indicated in the drawing by a section line. According to GOST 2.303-68, the section line is depicted as an open line, the thickness of which is one and a half times greater than the visible contour line. The length of its strokes is chosen from 8 to 20 mm, depending on the size of the image. The strokes of this line should not intersect the outline of the image. Arrows indicating the direction of view are applied from the end of the stroke at a distance of 1/3 of the length of the stroke (Fig. 25). The same capital letter of the Russian alphabet is placed at the beginning and end of the section line.
The cut should be marked “A-A”, i.e. two letters separated by a dash.
The size of the letters at the section line and in the inscription marking the section is larger than the size of the digits of the dimension numbers in the same drawing, and corresponds to the size of the capital letter of the standard font closest to the larger font in which the dimension numbers are written (see Fig. 24).
Every cut contains a section that is shaded.
Depending on the position of the cutting plane relative to the horizontal projection plane, all sections are divided into:
horizontal– the cutting plane is parallel to the horizontal projection plane (Fig. 26). Horizontal sections are usually located at the location of the top view or bottom view.
Vertical– the cutting plane is perpendicular to the horizontal projection plane. A vertical section is called frontal if the cutting plane is parallel to the frontal plane (for example, at the site of the main view, Fig. 27), and profile if the cutting plane is parallel to the profile plane of projections (for example, the section at the site of the left view).
Oblique– the secant plane makes an angle with the horizontal projection plane that is different from a straight line (Fig. 28).
The incision is called longitudinal, if the cutting plane is directed along the length or height of the object (see Fig. 26, 27).
The incision is called transverse, if the cutting plane is perpendicular to the length or height of the object (Fig. 29).
For horizontal, frontal and profile sections, the position of the cutting plane is not indicated; the cut itself is not marked with an inscription in the case when the cutting plane coincides with the plane of symmetry of the object as a whole and the corresponding images are located in a projection connection (for example, the section is in place of the main view, see Fig. .27).
All of the above cuts apply to simple– they are performed with one cutting plane; if there are several cutting planes, the cuts refer to complex(Fig. 30).
The cuts made when depicting a given object are independent of one another.
In a complex section, strokes of the section line are also drawn at the bends of this line. If necessary, the same capital letter is placed at the bends of the section line as at the beginning and end of this line. On the section (image) itself, the demarcation lines of the cutting planes are not shown, i.e. as if the cut was made in one plane.
Complex cuts are called broken, if the cutting planes intersect (for example, section A-A in Fig. 31).
Complex cuts are called stepped, if the cutting planes are parallel (for example, stepped frontal section A-A, Fig. 32).
For broken cuts, the cutting planes are conventionally rotated until they are aligned into one plane. If the combined planes turn out to be parallel to one of the main projection planes, then the broken section can be placed in the place of the corresponding type.
So, for example, the inclined plane passing through the boss of the part (see Fig. 31) is rotated to a vertical position; Now both secant planes of the broken section are parallel to the profile plane of projections, and section A-A is placed in the place of the view on the left.
With broken cuts, the direction of rotation of the planes may not coincide with the direction of view. So, for example, the plane passing through the mounting holes in the base of the part (Fig. 33) is rotated clockwise to the frontal position, and the direction of view indicated by the arrow is opposite to the direction of rotation.
Rice. 31 Fig. 32
An incision that serves to clarify the structure of an object only in a separate, limited place is called local. The local section is highlighted in the view by a solid wavy line (Fig. 34, 35). This line must not coincide with any other lines in the image. In accordance with GOST 2.303-68, the thickness of a solid wavy line is taken to range from half to one third of the thickness of the solid main line of the drawing.
The local incision is not labeled or indicated.
In one image it is allowed to combine part of the view and part of the section. Hidden contour lines on connecting parts of a view and section are usually not shown.
In the case of connecting symmetrical parts of the view and the section, the dividing line is the axis of symmetry - a dash-dot thin line (see GOST 2.303-68), while half of the section is recommended to be placed to the right of the vertical axis of symmetry (Fig. 36b, 37) and below the horizontal axis of symmetry ( Fig. 36a). if a contour line coincides with the axis of symmetry (for example, an edge in Fig. 37), then this contour line is shown in the image, and the dividing line is a solid wavy line.
Part elements such as stiffeners and thin walls such as stiffeners are shown unshaded in the section if the secant plane is directed along the long side of the corresponding element (Fig. 38).
Rice. 38 Fig. 39
If group holes are in a round flange, end, etc. do not fall into the cut plane, then one of these holes is conventionally rotated to the cut plane and is shown cut, but this is not indicated or inscribed (Fig. 77).
Useless cuts should not be made (Fig. 40) if they do not reveal any internal features of the shape.
| Rice. 40 |
Inscriptions and letter designations related to types, sections and sections are placed parallel to the main inscription of the drawing.
Building views begins with the mental selection of the position of the part in front of the projection planes. Then select the number of views necessary and sufficient to identify the shape of the part, as well as the method of their construction.
The choice of the position of the part in the system of projection planes depends on its working position, manufacturing method in production, and shape. For example, if a part is made on a lathe, then in the drawing its axis of rotation should be located horizontally.
Types of drawing can be done different ways. Let's look at some of them.
Construction of views based on sequential drawing of geometric bodies that make up the shape of an object. In order to complete a drawing in this way, it is necessary to mentally divide the part into its simple geometric bodies, finding out how they are located relative to each other. Then you need to select the main type of part and the number of images that allow you to understand its shape and sequentially depict one geometric body after another until the object’s shape is completely displayed. It is necessary to observe the dimensions of the form and correctly orient its elements relative to each other (Table 8).
The construction of views based on element-by-element drawing of geometric bodies that make up the shape of an object is carried out using the techniques of deletion and increment.
When drawing a geometric body using the deletion technique, the shape of the workpiece is successively changed in the drawing by removing volumes similar to the methods of processing it by turning, drilling, milling, etc.
When drawing a geometric body using the increment technique, the volumes of the product elements seem to complement each other and are incremented.
8. Element-by-element drawing of geometric bodies that make up the shape of an object
Constructing views using a constant straight line drawing (external coordination method). A constant straight line in a drawing is a line drawn from the center of coordinates (point O) down to the right at an angle of 45° (Fig. 86).
The object is mentally placed in a system of projection planes. The axes of the projection planes are taken as coordinate axes. The projection connection between the top view and the left view is carried out using projection connection lines, which are drawn until they intersect with the constant straight line of the drawing and are built at an angle of 90° to each other.
The constant line of the drawing is, as a rule, used in cases where, based on two given views, it is necessary to construct a third view of the part (see Fig. 86). Having redrawn two types of parts, construct a constant straight line of the drawing and draw projection connection lines parallel to the OX axis until they intersect with the constant straight line of the drawing, and then parallel to the OZ axis.
The considered method of construction is called the method of external coordination, since the object is fixed in space relative to the axes of the projection planes, which are located outside the depicted object.
(If the drawing does not show the projection axes and it is necessary to perform a third view of the part, then you can construct a constant drawing straight line anywhere on the right side of the top view.)
Constructing views using internal object coordination. Internal coordination consists in the mental introduction of additional coordinate axes tied to the projected object.
Rice. 86. Construction of the third projection from two given ones using a constant line drawing
Rice. 87. Constructing views using a method of internal coordination of an object
The rules for depicting products on drawings of all industries and construction are established by GOST 2.305-2008. Images of objects are made using the rectangular projection method. In this case, the object is placed between the observer and the corresponding projection plane (Fig. 15). The main projection planes are the six faces of the cube onto which the object is projected; the edges are aligned with the plane, as shown in the figure.
The images in the drawing, depending on their content, are divided into kinds,cuts And sections.
The number of images (types, sections, sections) should be the smallest, but providing a complete picture of the subject when using the symbols, signs and inscriptions established in the relevant standards.
8.1. Kinds
View is an orthogonal projection of the visible part of the surface of an object facing the observer.
Types are divided into basic, additional and local.
Main types– views obtained on the main projection planes (cube faces). The standard establishes the following names of the main types (Fig. 16):
1 – front view (main view);
2 – top view;
3 – left view;
4 – right view;
5 – bottom view;
6 – rear view.
Rice. 16. Main types
If the arrangement of views in the drawing corresponds to Fig. 16, then the names of the types in the drawing are not signed. Main view of the item (main view) - the main view of an object on the frontal projection plane, which gives the most complete idea of the shape and size of the object, relative to which the other main views are located. If the views from above, left, right, below, behind are not in projection connection with the main image, then they are marked on the drawing as ""А"" (Fig. 17).
Rice. 17. Designation of a view located outside the projection connection
The direction of view is indicated by an arrow, indicated by a capital letter of the Russian alphabet, starting with the letter À. Drawings are also drawn up if the view is separated from the main image by other images (Fig. 18) or is not located on the same sheet with the main image.
Rice. 18. Identification of a view separated by another image
The font size of the letter designations is approximately twice the size of the digits of the dimension numbers. The arrows indicating the direction of view should be the same in shape as the dimensional ones, but larger, with a thickened linear part.
Additional views– images on planes not parallel to the main projection planes. They are used in cases where any part of an object cannot be shown in the main views without distorting its shape and size.
An additional view is marked on the drawing with an inscription like ““А””, and the image of the object associated with it should have an arrow indicating the direction of view, with a corresponding letter designation (Fig. 19).
Rice. 19. Location of additional views
The additional view can be rotated relative to the specified viewing direction, while maintaining the position taken for a given object in the main image. In this case, the sign “” is added to the inscription ““А”” (Fig. 19), replacing the word ““rotated””.
The dimensions of the arrows indicating the direction of view and the sign are shown in Fig. 20.
Rice. 20. Arrows for additional and rotated views
When an additional view is located in direct projection connection with the corresponding image, the arrow and view designation are not applied.
Local view– an image of a separate limited area of the surface of an object on one of the main projection planes (Fig. 21).
Rice. 21. Image and designation of a local species
The local view may be limited to the cliff line, as small as possible, or not limited. The detail view should be marked on the drawing in the same way as the supplementary view..
Basic, additional and local views are used to depict the shape of the external surfaces of an object. Revealing the shape of the internal surfaces of an object with dashed lines makes it much more difficult to read the drawing and complicates drawing dimensions. Therefore, to identify the internal (invisible) configuration of an object, they use cuts and sections.
BUILDING A PART DRAWING
Lesson objectives:
· study techniques for constructing elements of solid models;
· master the techniques of constructing associative drawings of parts with main, local views and detailed elements.
Features of constructing solid models of parts
Any part can be represented as a collection of various geometric bodies; techniques for constructing solid models are discussed in lesson No. 3.
Fig.84 Solid model of the “Support” part
As an example, consider the sequence of constructing the model of the “Support” part, shown in Fig. 84. The construction of a solid model of a part begins with the construction of a base, to which various elements are then sequentially glued or cut out of it.
1. Select the projection plane on which the sketch of the base of the part will be drawn.
For the “Support” part, select a horizontal plane ZX and orientation Top.
On a horizontal plane, draw a sketch of the base - a rectangle in the center with a height of 60 mm and a width of 100 mm (Fig. 85), which we will extrude by 30 mm (Fig. 86). Any operation (extruding, gluing, cutting, etc.) is completed by clicking on the Create object button.
Fig.85 Sketch of the base of the “Support” part
Fig.86 Base model
2. To construct the upper element of the part - a rectangular tetrahedral prism on the upper plane of the base, draw a sketch - a square with sides of 40 mm (Fig. 87) and glue the prism by extruding 50 mm (Fig. 88).
3. To create a cylindrical hole on the upper edge of the prism, draw a sketch of the hole - a circle with a radius of 15 mm (Fig. 89) and cut out the hole by extruding to a depth of 40 mm (Fig. 90).
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| Fig.89 Sketch of hole | Fig.90 Hole cutting operation |
4. To construct stiffeners on the frontal projection plane, we will construct a sketch (Fig. 91), for which we will first make markings using auxiliary straight lines. The sketch must be drawn with a segment (line type - main), auxiliary straight lines are used only for preliminary constructions.
Fig.91 Sketching a stiffener rib
Fig.92 Selecting rib thickness
5. To construct stiffeners, use the Stiffeners button. On the command properties panel (Fig. 92), the Thickness tab allows you to select the Thickness of the stiffener. The Parameters tab allows you to define:
· The position of the stiffener relative to the sketch plane (Fig. 93);
The In sketch plane switch is used if it is necessary to construct a stiffening rib, the middle plane of which or one of its side faces should be located in the same plane as its sketch. Let's select this switch.
The Orthogonal to sketch plane switch means that the edge will be located perpendicular to its sketch plane.
Fig.93 Construction of a stiffener
The direction is shown on the screen by a phantom arrow in the model window. To construct the second stiffener rib, we repeat all constructions (Fig. 94).
Fig.94 Part with constructed stiffeners
6. In order to round the vertical corners of the base of the part, use the Rounding button (Fig. 95), set the rounding radius to 10 mm on the properties panel and point the cursor to the edge of the base. Then click the Create object button.
Fig.95 Construction of edge rounding
7. To alternately cut out by extruding to a depth of 15 mm two holes located on the stiffeners, we will draw sketches - circles with a radius R 3 mm. Having indicated the inclined plane on which the sketch will be drawn, select the orientation – Normal to... (Fig. 96).
Fig.96 Sketch of hole
The constructed model of the part is shown in Fig. 84.
CREATING ASSOCIATIVE VIEWS OF A PART
Active view
Techniques for constructing basic associative views (front, top, left and isometric) are outlined in laboratory work No. 3. Let’s construct the listed associative views of the “Support” part. It should be noted that active, i.e. Only one of the drawing views can be available for editing (changes). To make the view active, double-click the left mouse button on the overall frame of the view. The Current View field displays the number or name (this depends on the setting made in the View Options dialog) of the current view. To make another view current, enter or select the desired number (name) from the list.
Let's look at techniques for editing constructed views. Moving views with the destruction of projection connections is discussed in lesson No. 3.
Removing and destroying views
To delete or destroy a view, follow these steps:
1. Select a view by clicking on the overall frame around the view. A sign that a species is highlighted is the presence of an illuminated green outline around it.
2. Right-click inside the overall frame to open the context menu (Fig. 97).
Rice. 97 View editing context menu
The context menu switch Delete view allows you to erase the selected view.
The Destroy View switch allows you to destroy a view that previously existed as a single object into separate primitives (segments, circles, etc.). Only in a destroyed view can individual elements be erased, changed or moved.
Constructing additional views along the arrow
Elements of parts located on inclined planes are distorted when constructing main views. For example, the cylindrical holes on the stiffeners of the “Support” part in the top and left views are distorted - instead of circles we see ellipses. It is difficult to set the diameters of these holes in such views. In order to avoid distortions, an additional view is constructed along the viewing direction perpendicular to the inclined plane, shown in the drawing by an arrow.
For building additional type you should do the following:
1. Let's make the front view active.
2. Let's draw a look arrow using the Look Arrow button located on the Symbols page of the Compact panel (Fig. 98).
Fig.98 Designation page
First, the starting point (tip) of the arrow is indicated, then the second point that determines the direction of the arrow is indicated. The third point determines the position of the inscription. The inscription is created automatically; in the Text field on the Properties Panel at the bottom of the screen, the letter proposed by the system to designate the gaze arrow is displayed; you can select another letter from the context menu of this field.
To capture an image, click the Create Object button on the Special Control Panel.
3. Let’s build an associative view along the arrow using the View along the arrow button located on the Associative views page (Fig. 99).
Fig.99 Panel buttons Associative views
After specifying the view arrow, a view phantom will appear on the screen in the form of an overall rectangle. The arrow view is located in projection connection with its reference view, which limits the possibility of its movement (Fig. 100). The connection is disabled using the Projection Link button on the Options tab.
Fig. 100 Construction of a view along an arrow
Building a local view
The arrow view for the “Support” part was built only to show the shape of the holes on the stiffeners without distortion, and the view of the entire part was not needed. In order to show a limited area of detail, local views are used. For building local species it is necessary to indicate its boundary (closed contour). Contents of the view that are outside the selected outline will no longer be displayed on the screen (Fig. 101).
Thus, a detail view is created by cropping an image of an existing view of the model.
Let's build a local view according to the following scheme:
1. Let's make the constructed view along the arrow current.
2. Let us limit the area with the hole in the arrow view by a circle of arbitrary radius. The radius of the circle is selected from the following considerations: in the constructed local view, only a part of the view inside the circle will remain, and everything that is outside the circle will not be depicted.
Fig. 101 Construction of a local view
3. Using the Local View button on the Associative Views page (Fig. 99), we build a local view for which you can select your own scale, for example, 2:1 using the context menu for editing the view (Fig. 97), which is called up by right-clicking on the selected form. When changing the scale, the local view designation should be changed: A (2:1).
Constructing a callout element
In cases where it is impossible to show small elements of a part with all the details in the main views, callout elements are used.
A detail element is an additional separate image in an enlarged view of any part of the part.
As an example, let's consider the construction of a remote element that allows us to depict the groove near the cover in more detail in Fig. 102. To create a detail element, perform the following steps:
1. Draw a contour limiting the extension element using the Extension element button located on the Symbols page (Fig. 98). First, specify the center point of the contour limiting the extension element, then specify the dimensions of the contour and specify the starting point of the flange T2.
Fig. 102 Construction of detail detail
The shape of the contour limiting the extension element can be selected using the Shape button on the Parameters tab (Fig. 103); the flange direction can also be set using the Shelf button (Fig. 104).
Rice. 103 Selecting the contour shape Fig. 104 Selecting the direction of the shelf
2. Using the Detail button on the Associative Views panel (Fig. 99), we build a detail element. The magnification scale is selected from the window of the same name in the Parameters panel (Fig. 105).
Fig. 105 Selecting the display scale of the detail element
