Creating Multi-Sections Volumes

You can create a multi-sections volume by sweeping one or more closed section curves along an automatically computed or user-defined spine. The volume can be made to respect one or more guide curves.

This task shows you how to:

Before you begin: Create a 3D shape containing planar curves as sections and guides.
Related Topics
Working with Multi-Sections Surfaces

Create a Multi-Sections Volume

You can create a multi-sections volume by sweeping one or more closed section curves along defined guide curves.

  1. Click Multi-sections Volume in the Volumes toolbar.

    The Multi-sections Volume Definition dialog box appears.



  2. Select one or more planar section curves.

    The curves must be continuous in point.

    Tip: A closing point can be selected for a closed section curves.
    Multi-sections volume defined by three planar sections

  3. Optional: You can select a support surface for each of the extremity section curve.

  4. Optional: In the Continuity list, select the continuity type for each support surface.

    By default, the continuity is set to Tangent.

  5. If needed, select one or more guide curves.

    Warning: Guide curves must intersect each section curve and must be continuous in point.
    The first guide curve will be a boundary of the multi-sections volume if it intersects the first extremity of each sections curve. Similarly, the last guide curve will be a boundary of the multi-sections volume if it intersects the last extremity of each section curve.
    Multi-sections volume defined by two planar sections and two guide curves

    Note: You can create a multi-sections volume by sweeping a section curve along two guide curves intersecting each other at one extremity.

  6. Optional: You can select a support surface for extremity guide curves and select the continuity type for each support surface.

  7. In the Spine tab, select the Spine check box to use a spine that is automatically computed by the program or select a curve to impose that curve as the spine.

    Warning: The spine curve must be normal to each section plane and must be continuous in tangency.

  8. Click OK to create the multi-sections volume.

    The volume (identified as Multi-sections Volume.xxx) is added to the specification tree.

Impose Tangency conditions

You can impose tangency on multi-sections volume.

  • Choose the way you want to impose tangency conditions:

    You can make a multi-sections volume tangent to an adjacent volume by selecting an end section that lies on the adjacent volume. In this case, the guides must also be tangent to the volume. In Figure 2, a multi-sections volume tangent to the existing volume has been created:

    Figure 1

    Figure 2

Define Smooth Parameters

You can define smoothing parameters on the multi-section volumes.

  • In the Smooth parameters area, select:


    • the Angular correction check box to smooth the lofting motion along the reference guide curves. This may be necessary when small discontinuities are detected with regards to the spine tangency or the reference guide curves' normal. The smoothing is done for any discontinuity for which angular deviation is smaller than 0.5 degree, and therefore helps generating better quality for the resulting multi-sections volume.
    • the Deviation check box to smooth the lofting motion by deviating from the guide curve(s).