Mesh to Brep

I have a mesh that has color information in it and I would like to convert it to a series of surfaces while retaining the color information or at least retain a system to identify the panels by color.

I have found the componenets for making a surface out of the mesh faces but I lose all of the color information.

When I explode the mesh it gives color information but only by vertex and not by face.

I have tried to use the relative items but the vertex count and face count aren't equal. And when I cull it to take every fourth vertex color the pattern for the panels doesn't match the mesh.

Any Ideas.

I am basically trying to take the gradient pattern from the ladybug sun study and use it to assign panels by color to create a building facade.

Replies to This Discussion

Permalink Reply by David Rutten on October 18, 2013 at 8:10am

Meshes don't support colours per face. You can only assign colours per vertex. And surfaces don't support even that. There's two ways to bake a surface to Rhino with colour information, and neither is possible with the native set of Grasshopper components (though I think the first is possible with some 3rd party baking tools):

Bake the surface geometry with a custom colour. Every object in Rhino can have a colour associated with it, though usually this feature is switched off and the object inherits the colour of the layer it's in instead. Grasshopper doesn't have a mechanism for keeping a colour associated with a piece of geometry.
Bake the surface geometry with a material. You'll have to create a bitmap that -when applied to the surface- mimics the colour you're after. This approach allows even for gradients, but I have no idea how you would do it in GH.

Why not keep the meshes?

David Rutten

david@mcneel.com

Seattle, WA

Permalink Reply by Christopher DeFosset on October 22, 2013 at 7:01am

Thanks for the response David. I baked the meshes to maintain the color and then reassociated those to some grasshopper surface components and developed the panel I was after.

I didn't want to keep the meshes because I am not as familiar with meshes so I felt it would be easier to develop and manipulate the panel with breps.

Permalink Reply by Peter Liu on December 11, 2017 at 1:29pm

Hi David

I have a question based on this. I have an colorful image in Rhino and I try to get color data out of it.

Should I do mesh surface and then deconstruct mesh to get mesh vertex color?

But it doesn't work after trying it.

Peter

Thanks

Permalink Reply by Mostapha Sadeghipour Roudsari on March 31, 2014 at 12:47pm

Hi Chris,

I just saw this accidentally while looking for something else.

In case of Ladybug it is a little bit different. Ladybug unweld meshes which means vertices are not shared between the surfaces. I considered this so I can assign the same color to all the vertices of each face and generate a monotone color for each face.

You can recreate the faces in Grasshopper and assign the colors. Here is an example on how you can do it using the mesh:

Not to say that you can regenerate the colors based on the results if you still have them. Well I think I will assign the values to mesh points as userdata so you can retrieve it later. Added to wish list (https://github.com/mostaphaRoudsari/ladybug/issues/53)

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