how UV map related to texture, mesh-object???

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wretch1958
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Joined: Thu Mar 29, 2012 6:26 am

how UV map related to texture, mesh-object???

Post by wretch1958 » Fri May 11, 2012 11:57 am

I am newbie, just want to make sure I understand...

In UV editor I can open any image let's say mypic.png. I can also open it from properties (materials/textures) for object. I assume UV editor version is temporary, if quit Blender object materials/textures does not know about that image. We can see how it looks on object by viewing in Texture mode, but again is temporary. Rendering will not show it.

In object edit mode I select edges to mark as seams then unwrap. What appears in UV image/edit window is unwrapped mesh from 3d to 2d. This is a UV map. Can I save it (this UV map) to a file? "Export UV layout" exports a PNG, but UV map is just that, a mapping of 3D mesh edges to 2d mesh edges. Or can UV map only be saved as part of the mesh.

Back to the object properties, I select the image (png) as texture, then for "mapping/coordinate" select UV. UV and image are independent. How does it know which UV map to use? It just uses the last UV mapping created in the UV image editor? Can only one UV map be associated with any mesh, or can I specify which map to use form a list of saved UV maps?

The main problem I have understanding, how Blender relates UV map to mesh, can it be saved and/or managed, how can I see available UV maps for a given mesh or is this all hidden?

bill2reg
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Joined: Wed Feb 23, 2011 11:44 am

Post by bill2reg » Fri May 11, 2012 8:36 pm

If I understand you correctly, you need to click 'Assign' to map the UV image to the selected faces. Then you can also use a different image to map to different faces. Are you using Cycles render or Blender render?

wretch1958
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Joined: Thu Mar 29, 2012 6:26 am

Post by wretch1958 » Sat May 12, 2012 8:35 am

Sorry my questions were vague. Here is what I would like to do but cannot figure out how, probably don't understand UV mapping interface well enough.

1. In UV edit window, after unwrapping a simple cube, I am unable to move every island around independently. There always seems to be a pair that stick together?

2. I extrude the top of the cube in Z direction, then merge vertices to form a roof. Mesh is now house shape. Create UV map (I can now move all islands independently). I create a duplicate of the cube, want to use the same UV map on dup but different image. The new image is a copy of the old one but different colors (walls are grey instead of white, etc...) I keep ending up with same image mapped onto both houses (orig and dup)?

3. I create a new object cube (not duplicate) and extrude roof to create house. How do I use the previous UV map without recreating it all over?

bill2reg
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Joined: Wed Feb 23, 2011 11:44 am

Post by bill2reg » Sat May 12, 2012 8:43 pm

If you duplicate the object, you also duplicate its materials . But you can go to the materials properties panel of the duplicate and make it single user, then load a separate image as the new texture image, and then be sure to choose the new image from the drop-down list in the UV editor window as well.

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