Projecting the profile/silhouette of an object onto a Surface

I have an organic object as in the image below;

I am trying to project the silhouette/profile of the organic object to the surface behind it. I have tried couple of methods in grasshopper but all of them yield a really messy result like this;

I have tried the following;

  • Decon Brep, and projecting the points on surface. Then tried using the points to patch, which was way off.
  • Tried decon brep again, and this time using the edges, and projecting the curves on to the surface, which yields the result above.

Any ideas on what else I can try? (1.1 MB) (1.1 MB)
Not sure if this solution would work for what you are looking for.
I projected the surface as projecting the edges did not match the length of the vertex data set. The face was the most consistent.
I then projected the resulting surface onto the xz plane, as the surface is not flat. Then the boundary was taken. If the surface is a flat plane, you can project the object onto a flat plane and then take the region union on the plane.

1 Like

Is it not possible without projecting onto a flat plane such as t he xz one like you did?

As you said the surface I am projecting onto is not flat. I have posted only a small chunk of the overall surface, and this small chunk is almost flat. So there are areas where the surface curve is more obvious, and I am worried that projecting onto a flat surface first would start to deform things.

If there are no overlaps of the surface in the direction of the plane, then the above would be fine.
However I have a problem with the way the surface is being projected.
It looks as though you are attempting to do a closest point projection which distorts your brep.
I would recommend the pull curve component to move the edges onto the surface.
I am unable to come up with a solution general enough to cover all possible cases. The final surface would be required to find the solution specific to this case.

It’s difficult to make a proper solution by looking only at a part of the problem.
Your surface (that baked turn into a polysurface!?!) is almost flat, that make one think it’s always like that…

See if this can be useful: (1.1 MB)

What you have works perfectly on that section, but it doesn’t work when I try it on the bigger chunk, which I attached here. It leaves a line only this big; (4.4 MB)