Crease and Break Points

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Hello,

I was wondering if anyone knew what break points in a carve SOP does… Also, does anyone know what the crease function means (inside a primitive SOP attribute tab)?

Thanks :-)

Jane
Jane C
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Hi Jane,

Jane
Hello,

I was wondering if anyone knew what break points in a carve SOP does…
The following is extracted from the Geometry.fmk.pdf file, pg 91:
ONLY AT BREAKPOINTS
Performs cutting or extractions at breakpoints for curves and surfaces, at vertices for
polygons, and along isoparms for meshes.
By default the Only At Breakpoints option will only cut the outer breakpoints within
the specified interval. By enabling Only At Breakpoints, the U and V divisions
parameters are replaced with Cut At All Internal <U/V Breakpoints, which cut the
primitives at all breakpoints falling within the specified interval when enabled.
Please try the following:

Sphere SOP ( Nurbs) -> Carve SOP (turn on “Only at Breakpoints” & the “Second U” parameter)

Change the value of either the first or second U or both & see the difference when you turn off “Only at Breakpoints”.

Also, does anyone know what the crease function means (inside a primitive SOP attribute tab)?
The Crease parameter allows you to affect the “sharpness” of subdivided polygons.

Please try the following:

Box SOP (defaults) -> Subdivide SOP (Depth = 3, Turn on “Override Crease Weight Attribute” & set the value to 2.9)

Notice how the subdivided geometry is having almost “sharp” edges?

Next, turn off “Override Crease Weight Attribute” & insert a Primitive SOP between the two SOPs. Turn on the Crease parameter & set the value to 2.9. Notice the same result?

There's also a Crease SOP available if you want to have more fun!

I hope the above helps!

Cheers!
steven
Edited by - Feb. 11, 2003 20:51:11
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Hey Steven, that cleared up a lot. It helped me understand break points and creases a lot better, so thank you very much!

Jane
Jane C
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