CopyTrim Problem

Hello to everybody,

this is my first post here, allthough I've already read and learned many interesting things in this forum. Thanks for that... I hope you guys (and girls) can help me with a problem I encountered while using the CopyTrim Component in gh. First I want to say, that I'm on a very beginner Level regarding Grasshopper, so maybe one of you know a much better way to solve my problem.

I'm using the CopyTrim component to apply a planar 2D shape, that I drew on the X-Y-Plane, on a 3D-Surface that I constructed and extruded in a previous part.

First I am building the Shape for the 3D-surface, extrude it and afterwards I unroll the Surface on the X-Y-plane, so that I have roughly the size of the 3D-surface as flat surface. After that, I use the unrolled Surface to construct the 2D-shape that will be used with the CopyTrim Component. Finally I apply the 2D-shape that I have just constructed on the 3D-surface that was build in the beginning.

The Problem:

As you can see in the last screenshot below, the 2D-shape that I constructed with the help of the unrolled Surface, doesn't correspond to the projected Shape from the CopyTrim Component. I tried different things and scenarios, but the two Shapes are never identical. Can someone tell me why the CopyTrim component is behaving like this? Or did I misunderstood the functionality of this component?

best regs,

Peter

Replies to This Discussion

Permalink Reply by Hyungsoo Kim on December 21, 2015 at 5:48am

Hi.

I guess the problem is that your 3D surface has uneven U & V domain otherwise the unrolled surface has even one.

Try to rebuild your nurbs curve(ie: using "Rebuild Curve" component with degree 3, 6~12 control points count) before extrude & unroll.

Permalink Reply by Peter Noisten on December 21, 2015 at 6:25am

Hi Hyungsoo Kim,

your solution worked perfectly, thank you very much :)

I already heard something about different UV domains of surfaces, but I couldn't really unterstand it. Could you maybe explain to me, why the extruded surface has different uv values than the unrolled surface, and if it also has something to do with the uv values of the 2D-shape that U want to project on the extruded one? Because both curves (the first one for the extruded 3D-shape and the 2D-Shape for projecting) are built by using the nurbs-curve-component, so has it maybe something to do with the extruding process, cause I use the unrolled surface just to cut aus the 2D-shape.

I Hope you can explain it to me ;) and thank you again for your help.

best regs,

Peter

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