Optimal Handling of Large CAD Drawings

HiCAD enables a rapid and convenient creation and processing even of very large CAD drawings, which can nowadays consist of several thousands of parts. For optimal orientation within such complex drawings and a fast and efficient processing of large assemblies we recommend that you read the hints and tips given below.

Large assemblies
The question whether an assembly can be called "large" does not only depend on the number of parts of which the assembly consists, but on a combination of the following factors: The number of parts, the complexity of the individual parts and the number of solids / surface parts. In addition, assemblies are not infrequently imported via various interfaces. These imported models often have even more surfaces than necessary.

Part structure
The part-oriented HiCAD data structure enables you to create drawings the logical structure of which matches the part structure of real products. Before you start your drawing, it is therefore advisable to consider the product structure and create the part structure accordingly.

Referenced 3-D parts
References part are parts can be used for different projects and throughout the entire company. From an engineer's point of view, they can be managed and modified in a very convenient way. Therefore, save your sub-assemblies as referenced parts. When you work on a sub-assembly, just open the referenced assembly in a separate drawing and edit it there. Your main assembly will be updated automatically.

Opening of drawings in "reduced" mode
For a faster assembling of models, HiCAD offers the option to open CAD drawings with reduced data. In the process, referenced 3-D parts and assemblies will be represented as "reduced" elements, i.e. HiCAD will display them as polygon models, thus reducing the amount of data significantly. As a result, less memory will be required, and the general performance will be increased. The reduced representation can take place immediately when opening a drawing file is opened, or subsequently for individual parts and assemblies.

Exact and simplified representation of standard parts
Beams, profiles, standard parts, standard processings and boltings can either be displayed in an exact or simplified mode. Especially in large drawings containing many profiles, boltings etc. it can be useful to select the simplified representation.

Layers
Using layers allows the drawing to be split into different information components, which can then be processed individually, as required. For example, objects can be assigned, even temporarily, to the invisible layer 0.

Views

3-D parts can be hidden in certain views, either directly in the ICN or by defining so-called list views.

If you use the "real" Hidden Line representation, you have the option to hide parts that are overlapped by other parts. All parts which are not visible in the current view anyway, will then no longer be considered for further processings or recalculations of the view. Especially in the case of complex drawings, this will speed up the processing times significantly.

Besides the possibility of hiding views you can also "freeze" views. In contrast to hidden views, "frozen" views will remain visible on the screen, but cannot be processed. This option is useful if you have several views on one sheet, but work in only one view.

Visualisation settings
You can use the Visualisation Settings to hide parts with certain attributes as well as certain element types.

Active part
All parts except for the active part can be hidden in one step.

Part search
Use the Search function for a rapid detection of parts with particular properties.

Part selection filter
Resrtict 3-D part selection by setting appropriate filters.

Multiple selection
Define Part lists to process several parts in one step.

Shading mode

Two shading modes are available for 3-D models - Quick and Exact. The Quick mode is recommended during the construction phase. Before forwarding your shaded models as a print-out or as a pixel graphic, you should then choose the Exact mode.

Hidden Line calculation can be rather time-consuming for very large CAD drawings. For a faster handling, you can use the Quick Hidden Line or Quick Hidden Grey representation instead, which are optically very similar to the real Hidden Line representation.

The surface approximation determines the quality of the screen representation of filleted surfaces. The higher the value for the surface approximation, the "cleaner" and more precise will the shading look. Please note however that the file size will also increase. If the chosen value is too high, this may result in a loss of performance, especially for large drawings. We recommend the setting Via distance tolerance, with maximum/minimum number to obtain a good representation combined with a high performance.

Snapshots in long feature logs
If you have very long feature logs, insert so-called "snapshots" into the feature log to speed up recalculation. Recalculations will then only be performed starting from the last snapshot above the changed feature step. In this way, a time-consuming recalculation of the entire feature log can be avoided.

Threshold value for simplified OpenGL
The setting for threshold values enables the automatic simplification of parts starting from a particular size:

Parts that are smaller that 1 pixel are automatically hidden on the screen.

Parts that are smaller than 10 pixels are represented as cuboids on the screen.

This setting can be adjusted to the individual requirements of the user. You can change the pixel size for this dynamic switch of display individually in the Configuration Editor, at System settings > Visualisation > Views. You use the parameters

Threshold value for simplified OpenGL representation (Bounding box) and

Threshold value for simplified OpenGL representation (Omit)

for this purpose.

OpenGL and Graphics card
By default, the capacity for OpenGL display lists is unlimited, i.e. HiCAD uses the full OpenGL capability of your graphics card. The setting is specified in the file GRAPAR.DAT in the HiCAD SYS sub-directory. (Line 69/70).

Kapazität für OpenGL-Displaylisten [Capacity for OpenGL display lists]

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If you do not want to use the full OpenGL capacity of your graphics card, e.g. because you do not use a 64Bit processor or have a memory of < 4 GB, you can change the value accordingly, e.g. to 1000000 (default setting of older versions).

Please note:

Tips on performance optimisation can also be found in the ISD Wiki, at Product know-how > Whitepaper > HiCAD - Performance Optimisation.

If you want to simplify very large and complex CAD models before passing them on to a third party you can use the functions of the Simplify tab. This can be useful for very large drawings the processing of which would take too much time, or if you want to provide a partner or customer only with the absolutely essential information about the model.