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Subject: UV mapping trick


litst ( ) posted Sun, 22 August 2004 at 9:10 AM · edited Tue, 26 November 2024 at 8:14 AM

file_124131.JPG

Hi, i was playing with the UV editor of CS 3 and discovered something very useful :-) . I'm still new to it, so maybe you already know the trick that follows ... In the case of this dragon, it may be hard to UV map it . Usually sperical mapping works well for heads, but this one's not human and spherical mapping would lead to major distortions . So planar mapping on the profile axis is the solution, but creates distortion in the area of the seam, in the middle line of the head . Here's the trick i've found : 1 - i've selected the middle line and scaled it up a bit . 2 - i've edited the UV, selecting planar mapping on the profile axis : X . 3 - Here's the trick . Once the UVmapping is done, back in the vertex modeller, i've been able to undo the changes i've made to the middle line while keeping the UV mapping i've made . This technique makes UV mapping in Carrara more interesting than i first thought and i got the feeling it will often prevent me from moving vertices one by one in the UV editor :-) . The result, even though it's not perfect, shows that distortion is very reasonable, and this was done very fast ! Ha, just in case you're wondering, this is not the final texturing, only a snake skin procedural shader . litst


litst ( ) posted Sun, 22 August 2004 at 9:26 AM

file_124133.JPG

Here's an image that shows the benefits of this trick better .


mdesmarais ( ) posted Sun, 22 August 2004 at 12:36 PM

Cool- so the mesh is distorted (sort of unwrapped) for UV purposes, then moved back. . . Looks like you might want to expand the area over the eye and do the same thing? Markd


mateo_sancarlos ( ) posted Sun, 22 August 2004 at 2:15 PM

Yes, it looks much better with the trick. It may be topologically equivalent to the "edge-stretching" technique in UVMapper Pro, which I can't use (no Mac OS version).


nomuse ( ) posted Sun, 22 August 2004 at 4:02 PM

Aha. Unwrapping the model itself, eh? Nice results, too. I've been discovering myself that UVmapping has to be integrated into the modelling process early on. Tough for me, as I like to go back and tweak constantly. Perhaps it will break me of that habit, too! Just did a bow recently in which I created a tapered cylinder, UVmapped it, THEN bent and duplicated it. That worked great. Unfortunately I had to add a few details at the ends....and I discovered Carrara won't shift UV's when you do a simple extrude (as in, all my new faces were right on top of the old faces). Sigh. I'll keep your method in mind in the future, too.


brainmuffin ( ) posted Mon, 23 August 2004 at 1:04 PM

Attached Link: http://www.buckrogers.demon.co.uk/3d/3d.htm

Judging from the control cage, I'n going to guess that you've got the real-time subdivision set on 1, right? that mesh looks dense enough to smooth out on 1.... Some more tips for the UV mapper: (these work very well if you're exporting to Poser) While building your mesh, make sure you name any hard to reach polygons like teeth or tongue or the eyes, Stuff that's difficult to select in the UV mapper, because it's behind or inside something. (Selection:Name:Polygons [not polymesh.]) When you are done, export the model as an.obj file. Then open the .obj file, (you may want to run it through detriang first. Detriang can be found at the link above.)when you re-open it, check the following settings: Create Carrara Objects as: Vertex Primitives Create a single polymesh(needed for Morph Targets) Grouping: Create only one object Now, when you jump into the vertex modeler, select one of those hard to reach groups, like the teeth, (Selection:Select By: Name:Polygons) and create a new shading domain for it. (The shading domains will also carry over into poser as material groups). Now, when you go into the UV mapper, every part of the model will be accessable so you can make just one map, thanks to the settings we picked when we re-opened, and you can easily select the teeth(or whatever) under the Edition tab of the UV mapper, because we named them as a shading domain. you can edit each shading domain individually by selecting it under the edition tab, or, if you want to see the big picture, check off the "show all" box.


nomuse ( ) posted Mon, 23 August 2004 at 1:19 PM

Yah. Actually, you can do it without leaving Carrara by assigning shading domains. But I like having named groups for various reasons. Right now my workflow is to name as much as possible, export and use UVmapper to rough in the map, then back into Carrara to tweak the map. Export again and use text editor to rename or delete groups (changing about half of them to materials instead).


brainmuffin ( ) posted Mon, 23 August 2004 at 1:55 PM

The export/import is really just to take multiple polymeshes and put them into one. And, of course, to permanently subdivide the mesh, which needs to be done before uv mapping if you're going to output to Poser.


Vidar ( ) posted Mon, 23 August 2004 at 3:58 PM

Superb,thanks for the trick litst.


nomuse ( ) posted Mon, 23 August 2004 at 9:52 PM

Understand. I usually model it all as one polymesh with lots of named groups. And I use the "convert deformed object to mesh" to "freeze" the subD's. I wish Carrara could derive groups from the sub-D cage, tho -- I hate having to convert to verts then go through everything assigning groups poly by poly. Naming polys is fine by Poser. Creating usemtl statements is harder and I usually make those out of groups.


brainmuffin ( ) posted Mon, 23 August 2004 at 11:14 PM

"I wish Carrara could derive groups from the sub-D cage, tho -- I hate having to convert to verts then go through everything assigning groups poly by poly." I think it will.... I'll try it again tomorrow, but I think that if you have groups in the control cage when you export to .obj and re-open, those groups will still be there in the new denser mesh. I'm not sure which version of poser your using, nomuse, but when I save the obj with shading domains, Poser 5 will recognoze them. It just assigns a weird name to them. (like objectname.obj8 instead of teeth)


nomuse ( ) posted Tue, 24 August 2004 at 3:01 AM

Problem is on the Cararra side. I discovered that Carrara does not export a usemtl statement unless an actual material was created in the texture room. Since that was just one more thing to deal with I tend to ignore the material domains and use "name polygon group" for everything. At least, the preceeding was my experience under OS9, Carrara3 with latest Mac patch.


brainmuffin ( ) posted Tue, 24 August 2004 at 9:28 AM

mmm, hadn't even thought of that. I'm on PC......


thomllama ( ) posted Tue, 24 August 2004 at 12:05 PM

OK i'm lost with all this UVmapping stuff... I have read as few tutorials but every time I go to use it I just get a jumble of points that make NO since to the image. I have tried lots of combos of buttons/settings but never seem to get anything that makes since. reason I'm posting here is cause I see the image above and the UV map looks like the head, I'm trying a similiar item (llama head instead of a dragonbull... but basicly the same) My intention is to apply a UV map (grayscale) to be used by anything grows so i can have varying hair legnths. anyone got an idea what i'm doing wrong?






Hexagon, Carrara, Sculptris, and recently Sketchup. 



mateo_sancarlos ( ) posted Tue, 24 August 2004 at 1:34 PM

Thom, did you use flat (parametric) mapping?


thomllama ( ) posted Tue, 24 August 2004 at 2:59 PM

I don't see a place in the UV mapping to select that...






Hexagon, Carrara, Sculptris, and recently Sketchup. 



brainmuffin ( ) posted Tue, 24 August 2004 at 9:34 PM

Thom, To get a map like the one shown above, go to the projection tab on the UV mapper, and pick Planar from the little pull down menu. Then pick the axis you want, and split by orientation will split it based on which way the normals face, but split by position will let you choose where the split line is. Most times, split by orientation will do it for ya....


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