RapidForm Tips

601-20 Yeoksam-dong Gangnam-gu Seoul 135-080, KOREA
INUS Technology, Inc.
Boundary Fit Surface Generation in Rapidform XOR
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Create a fitting surface with 3D mesh curves as trim boundaries.
To use this command, a mesh with poly-faces and 3D mesh sketch curves are needed.
The dialog box shown below pops up by choosing Insert > Surface > Boundary Fit
Press OK with the proper options to create a fitting surface.
Parameter Guidelines
1. Some guidelines for creating Trimmed/Untrimmed surfaces:
a. Untrimmed surface
- Untrimmed surfaces are created with 4 edges of a trim boundary only.
Accept this, and trimmed surfaces are created.
b. The fundamentals of Trim Boundary Edge.
- When creating a surface by boundary fit, the segment between
interpolation nodes of a 3D mesh sketch curve becomes a unit edge. At this time, the edge is
decided not by topology of the curve, but based on the geometry. In other words, when the
deviation of tangent angles at the end points of neighboring curves is less than 3°, it treats
them as the same edge.
The following images show an example of a trimmed/untrimmed patch with 5 curves.
c. After splitting a curve, use the curve deform option to create an untrimmed surface. As
discussed above, since XOR considers that neighboring curves having deviation less than 3
degrees as the same edge, you need to deform the curve to have deviation less than 3
degrees after splitting it, as shown below.
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INUS Technology, Inc. Phone: +82.2.6262.9900 Fax: +82.2.6262.9999 http://www.rapidform.com [email protected]
601-20 Yeoksam-dong Gangnam-gu Seoul 135-080, KOREA
INUS Technology, Inc.
2. Regularize Overall Control Point Count
- Surface density is set with the By Allowable Deviation option (by default). In this case, under the
influence of local features or noise, the control points on neighboring patches could be very different.
Because of these control points, the geometry of a surface having low density could be changed
after matching, as shown below.
Before Matching
After Matching
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INUS Technology, Inc. Phone: +82.2.6262.9900 Fax: +82.2.6262.9999 http://www.rapidform.com [email protected]
601-20 Yeoksam-dong Gangnam-gu Seoul 135-080, KOREA
INUS Technology, Inc.
If you check the Regularize Overall Control Point Count option, the ratio of the number of
control points(actually the number of iso-lines) in neighboring patches are regularized not to
be less than 1/2. It avoids increased deviation and unwanted deformation of geometry, as
shown below.
Matching w/o Regularization
Matching w/ Regularization
Matching w/o Regularization (iso-lines)
Matching w/ Regularization (iso-lines)
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INUS Technology, Inc. Phone: +82.2.6262.9900 Fax: +82.2.6262.9999 http://www.rapidform.com [email protected]