About the View Generation Modes

You can specify the type of view generation mode when creating new views. This topic provides a detailed description of each view generation mode (including the advantages and restrictions pertaining to each one).

This page discusses:

Configuration of View Generation Modes
Exact View
Approximate View
Raster View
CGR View
Advantages and Restrictions Common to CGR and Approximate

Configuration of View Generation Modes

You can configure the view generation modes through Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting > View expander.

In this case, it is used while creating new views. For more information, see View.

Once a view has been created, you can modify its properties through the Properties dialog box. Right-click the view, select Properties, click the Generation tab, and then select the required options. For more information, see Generation Properties.

Important: In the case of CGR, Approximate, and Raster views, the generated geometry is not associative and cannot be detected. For these views, only interactive geometry and axes can be detected.

Exact View

Exact views are generated from the design mode, that is, they are the views for which the geometry is available. The exact generation mode is the best option in most of the cases, because of the following features:

This is the most accurate view generation mode.
All types of views can be generated using this mode.
Functionalities like dress-up, dimensions, annotations, are available.
You can generate them in shaded background mode. That is you can create exact views with visualization of a raster view.
Polyhedral data integration: Any kind of data from any exotic or regular CAD source (for example, polyhedral V4 .model data) are supported.

Note: The edges of faces with a relative angle of less than 0.5 degrees are considered as being smooth edges, and therefore are not represented.

However, there are a few cases for which choosing the exact generation mode is not be appropriate:

In the case of sophisticated products or assemblies involving large amounts of data, generating exact views may consume too much memory.
The edges of faces with a relative angle of less than 0.5 degrees are considered as being smooth edges, and therefore are not represented.

Clash Detection

Clashes correspond to the collisions between two parts in an assembly or two bodies in a part. Clashing bodies may be incorrectly projected in exact projection and section views: some edges of these bodies may appear whereas they must be hidden, or may disappear whereas they must not be hidden.

The image below shows clashing bodies in a 3D representation:

Using Clash detection option in Exact view identifies the location of the clash and gives a correct projection of the clashing bodies. When you select this option, the edges that are intersecting with other surfaces or volumes are split at the intersection point, and each of the parts of the edges are correctly projected.

The following table depicts this scenario in each of the view modes:


View Mode	Visual Representation
CGR
Approximate
Raster
Exact	With Clash detection option cleared:	With Clash detection option selected:

To avoid such clashes and ensure that the edge representing the border of the collision is projected, you can modify the assembly or part using either of the following methods:

Move the parts or bodies in such a way that the clash is avoided.
If possible, use Boolean operations (such as Add, Remove, Intersect, Assemble, and Union Trim in Part Design) to generate a single body resulting from the intersection.

To ensure that a screw in a threaded hole is not considered as a clash in a section view or a breakout view, you must design the screw as a whole 3D part representation, apply a thread feature to the screw, and create the hole as a threaded hole (see Part Design User's Guide: Creating threaded holes). Then, on the part instance associated to the screw, you must perform either of the following:

From the 3D part properties, specify its property to No cut. For more information, see Cut in Section Views Capability.
From the drawing representation, clear the Cut in section views option by using the Overloading Element Properties command.

Shaded Background Mode

You can generate an exact view in the shaded background mode. That is, you can create an exact view with the visualization of a raster view. This gives the look and feel of the 3D representation to the view. The view is an image of 3D geometry, or the raster view, with the capabilities of an exact view.

You can customize the preferences for the shading background mode in the View Generation section of the Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting > View expander. For more information, see View Generation.

In this mode, you can do the following:

Create the views of the 3D representation with the generated items including front view, isometric view, projection view, auxiliary view, unfolded view, view from 3D, section views and cuts, detailed views, and clipping views.
Hide or show the shaded background image on the view after the image is generated on the view.
Apply operators on the view to create breakout views, broken views, and 3D clippings.
Apply hatching and pattern to the sections. You can select the color for the hatching and dotting patterns. For color and image pattern, the selected color has no effect.

You can either generate views in the shaded background mode or you can also create views and then apply the shaded background image on them. To do so, right-click a view and select Properties. In the Generation tab, under the Generation Mode section, select the Shaded Background Mode check box. This is available for selection only for an exact view.

Shaded Background Mode

When you select this check box, in Generation Mode Options dialog box, under Shaded Background Mode Options, click Options, and you can customize the following options:

Mode: You can create views with Shading or with Shading, no light source. There can be a minor difference in the shading of the view because of the light source. You can select the With texture check box to represent the texture of the part in the view.

Level of detail (DPI): You can select the level of detail for the visualization mode and the print mode. There are four levels of detail for each mode:


Level of detail	Default value for visualization and for print	Editable values? (Yes or No)
Low quality	36.29	No
Normal quality	145.14	No
High quality	580.57	No
Customize	145	Yes

In the Hatching/Dotting Pattern Background for Operators area, you can customize the hatching or dotting pattern for background operators such as section views or cuts, callouts, details, and breakout operators.

Select Color from 3D to inherit the hatching or dotting pattern as defined on the 3D part. By default, this is selected.
Select Color from Palette to select the required color from the palette.

You can select the color for the hatching and dotting patterns. For fill color and image pattern, the selected color has no effect.

Note: If you generate a view in background shaded mode from a 3D representation, which has material applied to it, and then you change the material, you must manually update the drawing sheet to update the modifications.

Approximate View

Approximate views are generated using the Approximate mode. Although Approximate views are not as high in precision and quality as exact views, this generation mode dramatically reduces memory consumption. The performance can also be improved, depending on how you fine-tune the precision. Therefore, the Approximate mode is particularly well adapted to sophisticated products or assemblies involving large amounts of data.

3D wireframe geometry can be projected in Approximate views.

In the case of projection of 3D wireframe geometry, the only option applicable is Can be hidden which is available through:

Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting > View expander, under Geometry generation/Dress-up, select the Project 3D wireframe option, and click Configure.
Right-click the view and select Properties. In the Generation tab, under Dress-up, select the 3D Wireframe check box.

Polyhedral elements (such as surfaces or wireframes) from V4 .model documents are supported.

The Approximate mode offers about the same advantages and restrictions like the CGR generation mode (see About the View Generation Modes). However, there are some differences:

Approximate consumes even less memory than CGR.
Approximate is faster than CGR, but performance largely depends on fine-tuning.
Approximate provides more approximate results than CGR, but these results largely depend on how you fine-tune the precision.
Approximate lets you generate section views, section cuts, and breakout views. However, certain restrictions apply, which are documented in other parts of this user's guide, when appropriate.

For more information about the advantages and restrictions associated with the Approximate generation mode, see Advantages and Restrictions Common to CGR and Approximate below.

Raster View

Raster views are generated as images. This enables you to quickly generate overall views for large products or assemblies, regardless of the drawing quality. Such views are associative to the 3D geometry and can be updated when the part or product changes.

Restrictions

Raster views involve a number of restrictions:

You cannot generate the following types of views using this option: view from 3D, section views, section cuts, detail views, breakout views, unfolded views.
Raster views cannot contain dress-up elements (axis, centerlines, threads).
Creating dimensions is impossible.
Generally speaking, all commands requiring the selection of geometry are not available.
Raster views cannot be edited (you can work around this by isolating the view: double-clicking the image to start the image editor). However, the views generated in raster mode can be rotated.

As a consequence of these restrictions, selecting this option disables a number of other options in the View and in the Generation tab (available through Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting) or in the Properties dialog box.

Overloading Colors/Graphic Properties

When the color of a product instance is overloaded at the product level, this color is applied in the raster view to the elements contained in this product (including edges, faces, points, and lines).

When other graphic properties are overloaded at the product level, they are lost in the raster view (contrary to an exact view).

CGR View

CGR views are generated using the CGR format (CATIA Graphical Representation) of the 3D geometry. A CGR format only contains a graphical representation of the geometry, which is available with the Visualization mode (as opposed to the exact geometry, which is available with the Design mode). The CGR view uses and displays only the external appearance of the component and the geometry is not available. The corresponding .cgr file, if it exists, is inserted from the cache system.

To generate a correct CGR view from an assembly composed of .cgr files, use only the high-quality .cgr files, containing data about edges and faces. For example, a .cgr file created with DMU Optimizer misses this information (to be as light as possible). In this particular case, the CGR view mode can produce unpredictable results.

CGR views are not as high in quality as exact views, but they consume much less memory during the generation. This may be useful when dealing with sophisticated products or assemblies involving large amounts of data. However, this generation mode is rather slow.

For more information about the advantages and restrictions associated with the CGR generation mode, see Advantages and Restrictions Common to CGR and Approximate.

Advantages and Restrictions Common to CGR and Approximate

Using CGR or Approximate to generate views offers the following advantages:

Optimize memory consumption when generating and handling projection views for large products or assemblies.
Generate views from third-party data (such as Multi-CAD), as well as from polyhedral elements (such as dittos or surfaces) in V4 .model documents. Be careful in using only the high-quality .cgr files, containing data about edges and faces. For example, a .cgr file created with DMU Optimizer misses this information (to be as light as possible). In this particular case, the CGR and Approximate view modes can produce unpredictable results.

However, the CGR or Approximate generation mode involves a number of restrictions:

You cannot generate the following types of views:
- For CGR: section views, section cuts, detail views, detail view profile, breakout views, unfolded views and views from 3D.
- For Approximate: detail views, detail view profile, unfolded views and views from 3D.
The following types of elements are not associative on CGR or Approximate views:
- For CGR: Auxiliary view profiles, annotations, and dimensions.
- For Approximate: Auxiliary view profiles, and annotations. Dimensions can be associative, depending on whether you select the Allow the creation of associative dimension in approximate views option in the Dimensions associativity. See Dimension.
You cannot project 3D elements such as wireframe or points. on CGR or Approximate views.
CGR or Approximate views cannot contain dress-up elements (axis, centerlines, threads).
Persistence of editing the graphical properties (color, line type, line thickness, no show) and delete operations performed on generated elements are not available on CGR views but available on approximate views. However, as approximate views are based on the 3D representation (instead of the 3D topology for Exact Views) the associativity is limited. Therefore, if you modify a subpart of your 3D design, then the corresponding 2D representation loses any graphical changes that may have been made on it.
CGR or Approximate views being only a graphical representation of the geometry, only line segments are generated in such views. In case of non-associative dimensions (as is always the case for CGR views, and may be the case for Approximate views when the Allow the creation of associative dimension in approximate views check box is not selected), the only elements that can be dimensioned are these line segments. As a result, you may not be able create certain types of radius or diameter dimensions in such views.
CGR or the Approximate option disables a number of other options on the View and on the Generation tab (available through Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting) or right-click the view and select Properties.
Approximate items cannot be selected using the mouse (trap selection). However you can click to select and edit the properties of a single item. Note that you can also multiselect several items using the Ctrl key.
Approximate items cannot be duplicated. The Duplicate command is not available using context menu on an approximate item.
Approximate items cannot be searched using the Find command. They cannot be filtered by their graphical properties such as, linetype, color, or thickness.
The mesh thickness has an impact on the CGR and approximate view performance. Moreover, a CGR view cannot be computed from an extremely thin mesh, that is, when the mesh on a single face consists of more than 6500 triangles. In this special case, you must raise the 3D accuracy (through Me > Preferences > Common Preferences > Display > Performance section, under 3D Accuracy) before projecting a CGR view.

As a consequence of these restrictions, selecting either the CGR or the Approximate option disables a number of other options on the View and on the Generation tab (available through Me > Preferences > App Preferences > 3D Modeling > Mechanical Systems > Drafting) or right-click the view and select Properties.