Rails SOP


The Rails SOP generates surfaces by stretching cross-sections between two rails. This is similar to the Sweep SOP, but it gives more control over the orientation and scaling of the cross-sections. The first SOP input is the cross-section which will be replicated, and is typically placed in the XY plane. The second input SOP source is the rails along which the cross-section is replicated.


Parameters - Page

X-Section Groups xsectgrp - You can use a subset of primitives from the Cross-section input by specifying a group here. Accepts patterns, as described in Pattern Matching.

Rail Groups railgrp - You can use a subset of primitives from the Rails input by specifying a group here. Accepts patterns, as described in Pattern Matching.

Cycle Type cycle - - Select how the cross=section is applied along the rails.

  • All Primitives at Each Point all - Places all the primitives from the Cross-section input at each point on the backbone.
  • One Primitive at a Time each - Similar to the above, except the transformation is applied to individual primitives rather than to the whole.
  • Cycle Primitives cycle - This cycles through incoming primitives when placing them on a backbone. i.e. Start with 0 at vertex 0, primitive 1 at vertex 1, etc.

Sweep along Pairs of Rails pairs - Sweeps along rail 1 & 2, 3 & 4, 5 & 6 etc. instead of 1 & 2, 2 & 3, 3 & 4 etc.

Sweep along First and Last Rail firstl - Connects the cross-section between the first and last rails.

Stretch to Rails stretch - Stretches the cross-section geometry to the rail geometry.

Use Vertex usevtx - Specifies two vertices of the cross section polygon to be placed on rail1 and rail2 respectively. Very useful, for instance, to keep the first vertex on rail1 and the seventh vertex on rail2.

Connection Vertices vertex - - The vertices at which the cross-section is connected to the rails.

  • vertex1 -
  • vertex2 -

Scale scale - Global scaling of the cross-sections.

Roll roll - Non-cumulative rotation of the cross sections around the backbone. All cross sections get the same rotation.

Fix Flipping noflip - Option to correct the flipping when no direction vector is used and the two rails happen to cross each other causing the normal to flip upside down.

Use Direction usedir - Uses the direction vector specified in the X, Y and Z coordinates. Otherwise it will use the normals of the geometry.

Direction dir - - The direction vector to use.

  • X dirx -
  • Y diry -
  • Z dirz -

Create Output Groups newg - Selecting this option enables the creation of groups. A group is created for each backbone that is incoming. This allows for easy skinning in the Skin SOP.

Group Name railname - Specify the name of your output groups in this field. Accepts patterns, as described in Pattern Matching.

Operator Inputs

  • Input 0 -
  • Input 1 -

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