Texture mapping in rhino question

[iamcapitano]

Is there a way to texture along a curve within rhino? For example, the middle line in a road? I've looked everywhere and i haven't found anything!

[fooprobe]

Re: Texture mapping in rhino question

you can't render (& therefore you can't texture) lines/curves in rhino. you'd have to build a surface to be the stripe in the middle of the road. use your curve, offset both sides, loft. make sure it's a hair above the road surface.

[iamcapitano]

Re: Texture mapping in rhino question

I didn't mean render the curve, i just meant make a texture follow a surface with the curves as a direction guide :P

that sounds like the best method to use for single colours like a road line. What about an actual bitmap texture though?

I did this render in sketchup and as you can see in the curvy chair, the texture follows the shape of the chair accordingly, I modelled this chair in rhino and want to do the same thing but haven't been succesful. I textured the chair in rhino and exploded the surfaces to get that curvy side one, played around for a while but haven't discovered how to do it properly! do you know if it's possible in rhino?

[fooprobe]

Re: Texture mapping in rhino question

yes, you'd use the default mapping style called "surface" mapping. the texture will follow the UV lines of the surface. if you modelled the chair back as a solid and then exploded it, then the surfaces will still be using the default UV mapping for solids, which sort of wraps the texture around the whole solid. I haven't found the proper way to remove this default mapping, so i usually use the Rebuild tool on the surface, which resets the mapping so it will follow the curve of the surface.

anyone know the right way to do this (without rebuilding the surface?)

[iamcapitano]

Re: Texture mapping in rhino question

Ah you're right! it does work after you rebuild it and follows the shape nicely!

and i see what you mean with the problems of using the rebuild tool, you have to kinda guess the number of U and V values to keep the EXACT shape and not break it up....

luckily i know how to fix that

instead of rebuilding surfaces, you can "reupdate" the values to trimmed surfaces and such by simply using the "shrinktrimmedsrf" command and it makes the control points shrink to the current surface shape. I tried it and it works beautifully!

Good stuff

[fooprobe]

Re: Texture mapping in rhino question

there are also options in the rebuild dialog box for previewing the new surface and also calculating and showing the maximum deviation from the old surface, so you can get a sense of how close you're getting with the U&V values. shrink is perfect if the surface is trimmed, but it doesn't help for surfaces that are already shrunk or aren't trimmed (and it doesn't work on all trimmed surfaces).

[iamcapitano]

Re: Texture mapping in rhino question

Ah i see, hopefully rhino 5 will sort this stuff out as it really shouldn't be that complicated!

In my case for the chair shrink worked, except that on one or two trimmed surfaces, the surface options (uvw offset, rotation, repeat) are greyed out and no matter what i do i can't change them! the mirrored surface on the other side was editable so i simply deleted the problem one and mirror the one that worked, but that did seem a bit strange! have you experienced a surface who's surface projection settings were greyed out?

[fooprobe]

Re: Texture mapping in rhino question

Yes, it's the same problem. All the surfaces exploded from the solid will have the grayed out UVW options, which is why they don't map properly. It's some kind of hidden mapping that overrides the surface mapping. It won't go away even if you delete the channel and add a new one. When you use "shrink" rhino builds a new surface without the mysterious override, so it works properly. The surfaces you are talking about apparently can't be "shrunk", so you'll have to use rebuild.

[Micha_cg]

Re: Texture mapping in rhino question

In Rhino v5 is a great mapping type available - the custom mapping. You can project the mapping from one object to an other, from freeformed single surface to a polysurface. Maybe it helps here too.

PS: The mapped object can be copied to Rhino v4 or if this dosn't work, the extracted rendermesh exported as OBJ and reimported should keep the new UV to v4.

[fooprobe]

Re: Texture mapping in rhino question

awesome Micha - custom mapping works: by default it seems to use the kind of surface mapping you'd normally expect. i guess it uses the surface as the mapping object for itself? i have to spend more time with that one, looks like it can do a lot of interesting things...

but the surface mapping type is still broken, this still feels like a bug, time to talk to mcneel

[Micha_cg]

Re: Texture mapping in rhino question

Yes, it's not so stable yet, but I reported some bugs last and got the answer, that the next WIP release should be fixed.

[fooprobe]

Re: Texture mapping in rhino question

Ok, so I e-mailed McNeel and there IS a command that will reset the texture space of surfaces that used to be part of a solid, no rebuilding required: UnpackTextures

works like a charm

[Micha_cg]

Re: Texture mapping in rhino question

... only in some cases the unpack is lost after a reopen of the Rhino file. Than you must run the command again.