Is there a bug with the UV mapping settings in 3DXChange?

I import CC christian into 3DXChange. Exported his shirt, modified it in a 3rd party software and then Replace Meshed the original shirt with my modification. This worked fine but the modified mesh used the original UV as opposed to the modified UV from the modified mesh. So I repeated the process but this time deselected the "use original UV" check box during the Replace Mesh process. What I got was a new mesh that was totally corrupt (the import finished by the resulting mesh had points in wrong places). At first I though that it may be my 3rd party software creating faulty UV data but then I discovered that the same thing happens when you change the UV Type settings in 3DXChange or for original shirt.

The following image shows what happens to the original CC shirt when the UV Type is changed in 3DXchange:

   

As far as I understand, and please correct me if I am wrong, a mesh's UV data indicates how a texture map (or similar) is applied to the mesh surface. Normally the UV data of a mesh can completely distort or texture being applied to the mesh but generally it should not be able to change the shape of the mesh (the exception being that it can introduce transparent textures to parts of the mesh). If that is the case, changing the UV Type settings should not turn the original (unmodified) CC base shirt into a crazy poncho (as in the above picture).

This bug seems to be preventing the application of modified UVs when using the Replace Mesh option because when the "use original UV" check box is unchecked, the replacement mesh becomes similarly distorted (even if the user does not change the UV Type settings).

Is this a bug or am I doing something wrong?

P.S. I did try transferring the item from 3DXchange to iClone and it appears the same way in iClone.


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

This requires someone more expert than me, but if it works for non-CC meshes then it seems to indicate a bug.

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Thanks for the offer Swoop but as I said in my post the exact same thing happens with UNMODIFIED CC meshes (it may happen with non-CC meshes too...I did not try).

To re-produce:

1. Pull CC character Christian into 3DXChange
2. Click on the Shirt mesh
3. Go to the UV tab, change the UV Type settings and click Apply.

This is why I believe it to be a bug in 3DXchange/iClone and not my 3rd party software because the bug appears even without modifying the CC mesh.
(i.e. it can't be my 3rd party software if the 3rd party software never modified the mesh)

I will try with G6/G5 meshes and see if it also happens and then post the results here. I have a feeling I came across this issue a while back (i.e. with G5/G6 meshes) but did not report it at the time because I was new to iClone/3DXchange (and thus assumed I had done something wrong). 

EDIT: Added thanks.


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

I did a little checking and got the following results:

All meshes in CC characters, that allow changing the UV Type settings seem to be affected by this issue. This includes the CC meshes such as clothing but also the RL meshes such as the body.
All meshes in G6/G5 characters do not seem to be affected by this issue. I was not absolutely sure about G6 hair but I think the "change" that I observed was just the UV change and not a mesh change.

As I said, this issue is not a result of using modified meshes from 3rd party software because it appears when when the UV Type settings is changed on UNMODIFIED CC characters meshes.

If this is a bug, where can I report it formally so that it can get fixed in a future patch? As I said, this issue is currently making it impossible to Replace Mesh that has modified UV which makes the Replace Mesh function a lot less useful (since typically the replaced mesh will be distorted and thus require modified UVs). If anyone has a work around for this, please let me know. I have a CC Trench Coat ready to go but I would like to provide it with proper linear UVs as opposed to the non-linear UV that result due to the mesh modification.

EDIT: Please note that the above results were arrived at by spot checking...I did not verify all meshes and all G5/G6 characters. But the above pattern seemed to hold for all the spot checks that I did.


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

Hello , 

No problem for me to export and replace mesh with changing UV . But I can confirm th same issue , if you change UV setting on a CC clothed mesh (not on nude) inside 3dx6 , 

CGTRADER

Hi sw00000p,

My reply was just to confirm issue inside 3dx6 . For me no need to change UV setting for Character and cloth in 3dx6 . But inside any others 3d application , it can be beneficial to refine UVS .
I just test to change UVs shirt (CC Christian) inside max , replace mesh with my Uv , uncheck keep original Uv , apply to iclone and check inside iclone 6 my new uv ( just EZ push button to launch phtoshop and check my new uv map ) .

I think that it's useless to discuss here about the change of UV map ....

CGTRADER

I don't need to change the UV Type (UV Projection). Changing the UV Type is just a easy example of how applying a UV change (which should not affect the shape of the mesh) has unexpected results (i.e. seems to change the mesh shape) in 3DXchange. I needed a way to determine if the problem was due to my mesh modification (were I first noticed the problem) or if it was 3DXchange related.

By using an UNMODIFIED mesh and then changing a UV setting, in 3DXChange, I eliminate the possibility that the issue is introduced by external software (i.e. my mesh modification) because I have, for the test, eliminated all external software (i.e. used an UNMODIFIED mesh and applied a UV change in 3DXChange). Changing the UV Setting Type just happened to be an easy way to demonstrate this. I have not tried it but I am guessing that if some of the other UV settings in 3DXchange are applied then they will cause a similar problem.

I am guessing that when the user does a Replace Mesh and deselects the "use original UVs" check box, then the same 3DXchange function is called to update the UVs which results in the same issue (i.e. distorted mesh after UV update).


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

I have added this issue to the Issues thread.


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

Does anyone know of a work around (to get new UV when using the Replace Mesh option) until this bug is fixed?

Not being able to Replace Mesh with new UVs greatly diminishes the usefulness of the Replace Mesh to create other CC bases.


"We often compare ourselves to the U.S. and often they come out the best, but they only have the right to bear arms while we have the right to bare breasts"
Bowser and Blue, Busting The Breast

Like as said , no problem for me to change UV with replace mesh . 

CGTRADER