Hello:

I'm trying to take a 'displacement map' and make a real set of tight fitting clothes out of it with Maya. On the "Making of Ryan" video they showed a techique where you can draw a curve on a surface ('make live') then 'trim' a cut out.

I want to do this on a V3 model, but I'm having problems.

Is there a way to draw a curve on a polygonal object, then 'intersect' or 'trim' the curve away from the polys? I can't figure out how.

I tried converting V3 into a nurbs surface, but that was a bit of a mess :) (slow).

I've done this with a bitmap and used displament maps in Poser to do a half reasonable job (it's skin tight) but I want this to be an actual outfit.

Any ideas?

I'd post pictures but I don't have a Gallery account.

== John ==

I'll in part answer my own question - Instead of using one curve to cut out the poly object, I'm drawing several curves with points close to the 'outermost' poly's and then using Loft with the curves I just drew. It would be a lot easier if I could just trim the surface but at least this is working. I keep having to redraw the curves when they go 'inside' V3 however if I put the curve in the wrong place. It would be a lot easier if I could trim a polygonal object, however. == John ==

Do you mean like cutting a hole (or whatever shape) out of the model? Because you could use Booleans, although those can get messy.

The reverse of cutting a hole, but basically yes. You can use a boolean with the 'cutting' or intersection object being a curve? I didn't see how to do that, but I'm a n00b to Maya's UI. == John ==

I don'thave Maya open right now but I believe you can only make a NURBS surface a Live Surface? Also... The only way I can think to do that would be to make the curve, then extrude or loft, then turn that into polygons and then use a boolean... <---signature---> nemirc Animation Moderator

I can make V3 (simple OBJ import) a live surface, so that's not a problem. However, if the arc of the 3D curve I draw is 'over' the horizon any lofting around the curve will of course cut right through her. So far the best bet seems to be laboriously creating a series of curves with most CV's on top of the V3 polys. This will take, of course, forever. I'm also thinking of getting V3's reduced resolution - that might convert to NURBS a little easier. == John ==

Sorry, I may be a bit confused, but could you explain a couple things? My impression is that you want to take your "nude" model of a person, and basically draw out where their clothes should go (like the top and bottom areas), and then create a new surface between those boundaries? Then I assume you would scale that up a bit so it looked like it had depth...or use it in some way to create a displacement map? But the whole idea is you want to "detach" a portion of your model so that you can use that to make clothes? Also, when you say trim, do you mean you want to do a trim (a command used on nurbs surfaces), or are you using it as a non-Maya term meaning you want to cut your model up =)? If what I said above is the case, there are ways to do that with polygons that will be very different from using Nurbs. If the boundary where you want to extract already exists in the polygons, just goto paint polygon mode, and paint out the clothing area. Then goto "Edit Polygons: extract" or if you want to keep the originals "Edit Polygons: duplicate faces". Then you can simply move those faces away from the body, and you have your clothes to do whatever with. Also you could use the split polygon tool if there are polygons that you basically need to be "split" in half. Sorry if this isn't helpful, but if you answer the above questions I may have a better idea of exactly what you want to do and could help better =).

do you mean you want to do a trim (a command used on nurbs surfaces)<<

Correct.

Paint Polygons won't really work as the edges will be rather 'rough'. I did, however, think of that. The bigger problem is about 50% of the poly's remain so it's a lot of painting. (the curve took time too but not nearly as much as you only have to trace the outline, not all the interior polys).

One side question: is there any blasted way to prevent 'selection box' from selecting THROUGH an object?

Failing that, is there a way to make box poly selection NOT be toggle but rather 'on' or 'off'? (then I could just switch to the side view and selection box all the back face poly's to off.

(selection box means shift plus drag).

I did find I can make a displacement map of a polygonal surface and then boolean subtract (difference) the original surface - this gets me pretty close. I got a LOT of poly's with it though and somehow screwed up the displacment surface (it was pegged at 1.0 so of course it stuck out a LOT).

So my next try will be:

a) resize the displacement map to 512x512 or even smaller
b) copy V3
c) resize the copy by about 5%
d) apply the displacment map
e) Convert the displacment map to polygons (I'm at work, I Forget the command, but it makes the render time geometry displacement into actual poly's)
f) subtract c from e.

That'll get me really, really close.

I'm also looking at rail curves - I think I could draw outline curves then run a shape up the rail to project 'out' a little.

Man there's a lot of options in Maya.

I finally realized I can upload images if need be without a paid account, so I can post what I'm trying to do.

== John ==

Paint Polygons: You can resize the brush, so you could paint like half your model in no time at all. Selecting through an object: Goto Window: Settings/Preferences: Preferences... From there click on the Polygons category. Then find "Backface Culling" and turn it on. This will avoid selecting (and viewing) polygons that have their normal pointing away from the camera. Keep in mind, this means if you had a sphere, delete one face...it will look as though there is nothing on the other side, when in fact there is (the normal on the other side of the geometry is facing away from the camera, so it will not show up). Also, I have to restart maya after changing this option for it to take affect (not sure why). Toggle Select: Control and drag click always subtracts from selection. Control + shift click always adds to selection. And as you know, Shift click toggles selection. Not sure what else to say. The boolean idea I think would work, but I can't get booleans to do what they are supposed to on my computer right now. But if you had extra geometry, you could again just use paint selection and delete it.

Thanks, I never thought of backface culling affecting selection. Also, the toggle selection keys are a big help, again something I missed. Another idea I had was that if I didn't export my .obj with edges welded, I could probably convert the poly's to NURBS a little easier and then do a TRIM that way; it's a lot easier than converting all of V3 (especially the face poly's). For some reason my 3D painting seems to be really really slow, so I gave up on it. (GeForce 6600GT, Athlon 64/3700 San Diego core, 2 Gig RAM). I know what you mean about booleans, it takes minutes to subtract a V3 level object, so it's a 'do it and walk away'. So I only tried 2-3 times last night. I really like the idea of these displacement maps being convertable to Poly's - I think it could be a very easy way to model things. I think you pointed me in the right direction, I'll mess around with it some. == John ==