How to Work with Hole Features in BricsCAD Mechanical

Quick answer: Hole features are a simplified version of Form Features. SMCONVERT distinguishes between them by these rules: orthogonal holes and simple non-orthogonal holes count as hole features; chamfered orthogonal holes, or any hole whose thickness face is made of two different regions, count as form features instead. Holes recognize as hole features when SMCONVERTRECOGNIZEHOLES is on.

Basic Operations Allowed on Hole Features

• SMDELETE, SMDISSOLVE, Disable, and SMSELECT, either as commands or via the Mechanical Browser for Sheet Metal.
• Form Feature Modes within SMUNFOLD, including Symbol mode.
• Associating your own 2D geometry in a flattened layout.
• SMREPAIR preserves hole features, though plain hole faces become orthogonal, a hole feature that’s already the same geometry stays unaffected.

Recognizing Arrays of Hole Features

When a body contains hole features, SMPARAMETRIZE can detect rectangular arrays of them on flanges, following these rules: the holes belong to the same flange; they sit on a rectangular grid; there are no gaps (missing elements) in the array; every hole is equally oriented; and the minimal array size is either 1×3 or 2×2.

Worked Example: Recognizing and Parametrizing an Array

Starting from a part with Flange and Bend features:

1. Open the Settings dialog and go to Sheet Metal / Commands.
2. Enable Recognize holes for SMCONVERT.
3. Enable Convert holes to array and Parametrize holes for SMPARAMETRIZE.
4. Launch SMCONVERT via the Convert to Sheet Metal tool button on the Sheet Metal toolbar or ribbon panel, or Convert to Sheet Metal in the Sheet Metal menu. You’re prompted to select 3D solids, or choose Entire model.
5. Select the 3D solid to convert; you’re prompted again.
6. Press Enter to convert it into a sheet metal part; in this example, 11 hole features get recognized on the part.
7. Launch SMPARAMETRIZE via the Parametrize tool button on the Sheet Metal toolbar or ribbon panel, or Parametrize in the Sheet Metal menu. You’re prompted to select 3D solids to parametrize, or choose Entire model.
8. Press Enter to process the sheet metal part; the Command line reports something like:

Created 4 distance constraints
Created 3 fix constraints
Created 0 coincident constraints
Created 0 tangent constraints
Created 0 rigid set constraints
Created rectangular array 2x2 basing on Hole_3 feature
Created rectangular array 2x2 basing on Hole_7 feature
Created rectangular array 3x1 basing on Hole_9 feature
Total: 7 constraints and 3 array(s) created

Feature names and the exact constraint distribution may differ depending on your BricsCAD version. To examine the resulting arrays, temporarily unfreeze the BC_SUBTRACT layer. Note also that separate arrays sharing a flange aren’t unified together, doing so would introduce missing holes into the combined array.

9. Edit the resulting arrays’ properties in the Mechanical Browser, adjusting rows, columns, and spacing for each array as needed (increasing one array from 2×2 to 3×4, adjusting another’s X and Y spacing, and increasing a third from 3×1 to 5×1, for example).

Frequently Asked Questions

What’s the difference between a hole feature and a form feature? Orthogonal and simple non-orthogonal holes count as hole features; chamfered orthogonal holes, or holes whose thickness face is made of two different regions, count as form features instead.

What’s the minimum size SMPARAMETRIZE needs to recognize a hole array? Either 1×3 or 2×2.

Does SMREPAIR ever change the geometry of an already-orthogonal hole feature? No, only plain (non-feature) hole faces become orthogonal; a hole feature already matching that geometry stays unaffected.

How can I inspect the arrays SMPARAMETRIZE just created on a part? Temporarily unfreeze the BC_SUBTRACT layer to examine them.