Hi, i have simple object like the image below. Left cube is a clone of Right cube. when i unwrap uv, i paste uv from Right cube to Left cube, but the checker are not the same. I dont know why? Pls help me, thank you!
Paste UV to same object problem?
Hi. Just repeat the "Paste" operation again. Each time you use UV Paste in Unwrap, your "left" cube's UVs will rotate 90 degrees. In cases like yours, I would click "Paste" multiple times until the vertices will be oriented in the same direction as before and have the same UV mapping as the source.
Accepted solution
@Anonymous wrote:
I have done what you said but there is nothing happen. I notice that this issue happen when i use with mirror clone object. In this case, the left cube is mirror clone of right cube. I tried to paste uv several times but its not working.
I think the mirror caused the problem. When you mirror-clone an object, the poly mesh gets mirrored, but its UVs don't change. This creates flipped UVs. But when you use Copy/Paste UVs, the flipped UVs tries to unflip while taking on the shape of the source model's UVs. This method simply won't work on symmetrical model parts. I don't recommend using Copy/Paste of UVs on symmetry. Copy/Paste UVs are best performed on identical geometry.
Below workflow might sound like a lot of steps, but it's very simple. You basically need to unwrap UVs once when creating symmetry.
-What I would do is model and unwrap the UVs of the parts (right side, in your case) that need to be mirrored. Don't worry about the left part for now.
-When you finish unwrapping the right side, collapse the stack and delete the left part of the mesh if it's still there.
-Mirror those right-side parts that need to be mirrored. Then attach the clone(s) if using the Mirror tool, or collapse the stack if Mirror modifier is used. Don't weld the vertices yet. You want to keep these as Elements for easy UV selections later on.
-Apply Unwrap. You will notice in Edit UVWs window that the mirror-cloned parts are in complete alignment and overlapping with the original. Your cloned parts' UVs are now flipped because of the mirroring.
-You can now select the UVs of the mirrored parts by turning on "Select by Element UV" from the Viewport or Edit UVWs window. Go to "Tools" menu in Edit UVWs and choose "Mirror Horizontal." Or, use "Mirror Vertical" if it was mirrored vertically.
-Move selected UVs (Shift+Move if moving horizontally or vertically) in Edit UVs window and position them where you want and even Weld where neccessary. If vertices won't weld, then it's because they are separate mesh elements and/or don't share UV vertices. In such a case, collapse the stack, weld the mesh vertices, the re-apply Unwrap and weld the UV vertices.
Now you have a perfectly symmetrical model and UVs.
Note: When using Mirrors and Symmetry, always check for errors by using xView. Main menu > Tools > xView. Or, Viewport "+" sign > xView. If you are aware of the flipped UVs and already know that that won't be an issue later on, then you don't have to worry about it.
Also check for negative scaling when using Mirrors.
Negative scaling example:
-Create Sphere. Mirror on X using the Mirror tool in the menu bar.
-Select the Scale tool. The readout below the timeline will be "-100." This means your faces are flipped and will be a problem when exporting to other programs. For Max to correctly display negatively scaling, you will need to apply Reset XForm utility.