bug with Divide surface component?

Replies to This Discussion

Permalink Reply by David Rutten on September 24, 2012 at 4:56am

Divide surface does not generate points on the trimmed portions of surfaces. Are you sure that surface is untrimmed? Or does it have a thin sliver cut off along all edges?

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David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by kwanphil cho on September 24, 2012 at 5:27am

Yes. David. I am pretty sure that it is not trimmed surfaces. I just created simple planar srf from rectangular curves. It is working with rhino 4, not with rhino 5.  What is a thin silver cut off?

 

thanks

Permalink Reply by David Rutten on September 24, 2012 at 6:15am

A surface in Grasshopper can be trimmed. Trimming data consists of curves (usually called 'trims') that are joined together in closed loops. For example:

The green rectangle represents the untrimmed surface and the grey shape the trimmed part. This part is typically called a 'face'. There can be any number of trimming loops, but only one outer loop. When trimming loops intersect themselves or each other, the face is considered to be invalid.

For practical reasons we don't like to have freeform trim boundaries touch the edges of the underlying surface. We usually make sure the surface is slightly bigger than it needs to be to avoid trims coinciding with surface edges.

Sometimes when the face is very close in shape to a rectangle this causes confusion as there will be a thin strip of trimmed bits along the edges:

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David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by kwanphil cho on September 24, 2012 at 8:37am

I see.. but what I don't understand is that why this thin silver is generated. In rhino4, I used exactly the same method of creating planar srf. And it was not the trimmed surface but when I do the same thing in rhino 5, it says that it is trimmed surface. Is it intentional?