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hi, got a serious problem with preserving UVs never working on most of the models I work with (esp. when got the models from clients and imported it to maya). after using planar or auto to create a uv set for pieces of the models (typically walls) - if there are changes made to the geometry - the uv's are getting distorted. preserve UV's never works for some unknown reason. so after cutting, extruding etc. - I need to delete history and re-apply the projection. and if I have to do extra manipulating - again. really really annoying. I don't know why preserve UB's never works, and freezing the mapping didn't help, too. is it becuase I use maxwell materials or is there a better way to texture objects? PLEASE HELP !!

) That's normal behaviour of UVs in any software The way UVs are mapped - is they are assigned to vertex coordinates (and each vertex has a unique number and coordinates in space) that's how you can calculate a polygon face between 3 or more vertices.
So basically what you're experiencing is absolutely normal behaviour.
Now, the proper workflow would be to do your geometry first, and once done - do the uv, so that geometry will not be changed after your mapping.
Imagine you have made a t-shirt precisely for a body. but then suddenly you add another arm - your t-shirt will not fit anymore.
So in other words there is really little point to do UVs on geometry that its not final.
In your specific cases, with walls and straight corners, you can define areas that will not be changed and map those - just make sure to have those as separate individual uv shells - so that you'll have some areas mapped, while you're working with other areas. and once you're done - you can map the rest and match the ratio with the existing ones.

UVs in Maya are fairly easy tools are so convenient

thanks Nasok, however clients don't think like you they change stuff all the time. I wanted to try and work with the projection method but it appears it's impossible to do it with maxwell materials so I'm open to suggestions....

also the biggest annoyance is that when I try and manipulate stuff with "preserve uv" checked, maya does it but than snaps back to previous un-tweaked positions and prompts for an error. but damn it the viewport just showed me it can be done!

Hi choo-chee,

It is kind of tricky tool but it works if you follow some rules.
Did you check this video from malcolm341 on you tube?
https://www.youtube.com/watch?v=09VPtXcmDIo
Very good explanations.
Hope it helps
cheers ,
alex

There is no tool that will keep the UVs if you do extrude. Preserve UVs has a threshold .. and if borders are the same .. kinda it might work but it is still not a magic tool that will allow you to do everything you want with geometry and expect UVs to be the same .. I wish it would be like that - would made my life so much easier
@Choco-chee - yeah - usually clients don't really bother understanding the way it all works .. and that's fine.. All they need to know that it will require more time / budget if these changes has to be applied.

That's why the best result you'll get only if the geometry will be unchanged after UV mapping. Alternatively you can cut the amount of work by separating locked elements (the ones that you don't need to change) from variables (the ones that might change).
Also, if topology is more or less the same you can transfer attributes (UVs from similar models) ..
Oh, btw, normal projection should be a pretty good fit for your workflow, especially if you're dealing mainly with straight angles

thanks, gonna wath the video soon. couldn't use projection since maya will not let me connect it to maxwell materials...
*edit* well the video is nice but only for simple objects, not for complicated ones where I need it (like complete walls of a house...)

Yeah Maxwell is not a node based .. yet hopefully someday so it doesn't really work with all Maya nodes.
In your case you can still break your walls into a smaller simpler objects. And as long as you don't mess with border edges and don't change the amount of vertices - you should be okay .. ish

I was hoping maybe someone wrote a script or something so you can keep the uv projections "always on top" of all other history details, or freeze them so they don't get manipulated.... if you know of something like this please link me

)) sure - that would be the game changer .. but so far it is physically impossible since it is against the main principle of constructing the geometry in general Triplanar projection might save a bit but it will work with only abstract kinda textures - anything specific will be still heavily dependent on hand-crafted UVs.