Unwraping Complex Hard Surfaces

jocose

I have always found it really difficult to unwrap objects with lots of complex interconnected hard surfaces.

I was just wondering how everyone else goes about doing this. I have attached an image that shows the kind of problem I am talking about. With a model like this I may not always be able to take a modular approach, and you may also not want to overlap a bunch of shells, especially if I want to bake in ambient occlusion and only have 1 UV set.

If I do an automatic layout I get a layout that wastes a ton of space. However if I were to break up the shells then it would be very difficult to paint anything continuous.

Does anyone have any tips or tricks? Keep in mind I'm not talking about architecture, but rather smaller items such as scaffolding, cages, or simple mechanical devices that have lots of these types of boxes or cylinders.


Edit: Just to clarify I suppose I'm asking wether it makes more sense to break up all of these objects into separate UV shells or to merge them together. If you were confronted with a prop like this which route would you take?

rasmus

Well, I'd definitely fill all those holes with all the small stuff. Looks to me like everything already is in separate shells, and don't see how it would make sense to merge any of it, unless you want continous smoothing - just fill the gaps and leave room for padding and you should be good to go. Maybe try to keep related polys grouped together for less confusion when texturing.

Ben Apuna

It all really depends a lot on what you're planning to do with it. You could still overlap most of those little columns because their AO will be the same or close enough to not make much difference. The two corner columns on the left side can be stacked/mirrored. Both sets of rectangles look like they can be stacked/mirrored top to bottom. Even the top/bottom of the large cube could be mirrored. Only the column on the far right looks like it would have a different AO than all the rest.

EDIT: on second thought the two corner columns on the left can't be stacked as they will have different AO.

I also would've broken all of those rectangle shells on their corners and merged all the connected sides along their "long" sides while hiding the final seam toward the inside of the geometry. With this method it would probably waste less space in the end. If for some reason top/bottom of those rectangles need to be kept as one shell the just fill the holes like rasmus suggested.

I'm in the habit of merging as many shells as possible because it's easier to paint the textures, but if you have some normal map or engine specific reasons for leaving them all separate then do so.

Mechadus

Stuff like that is tough. perhaps you could merge some chunks on your UVs to make it easier to work with - like all 4 sides of one segment of your shape could be 1 UV island. Still a lot of work, but you could probably squeeze in a bunch more pixel space vs auto unwrap.


-N!

seforin

planar and stitching edges works fast all pieces similar (top bottoms) merge on top of another theres no real QUICK way but sometimes smart design of 3d shapes goes a long way (unwrapping with symettry and such

SHEPEIRO

I would make sure every seperate shell was a single UV shell, thus reducing vertex transform costs by quite a bit.... unless it was normal mapped from high but probably not for a shape like this, then i would put of the similar (exactly the same) peices over the top of each other.

for the rings i would stitch each section together with the split along the inner underside edge, then stitch the small outer edge to create a long single shell, this woul dbe much etter than what you have there as all the long exposed edges woul dbe connected, what you have only has the shortest edges of the top conected.

Rens

Play tetris... alot.

Mark Dygert

I would do like Rens and Remi suggested. But I would take your original layout, select all the long vertical faces, break/detach them, and stitch the long edges together so they so they fit like Rens layout.

El Burritoh

It's not straightforward, that's for sure.

While it's true that the AO may be the same for certain areas, and that therefore you could overlap those areas in the UV, doing so would force you to use the same texture space for those areas. And you might not want that. Your design might require differences in the texture to get the look you want.

All in all, the hard part for me is UVing this so that it's all to scale. I can't stand having to scale textures to match adjacent ones.

SHEPEIRO

El Burritoh wrote: »

It's not straightforward, that's for sure.

While it's true that the AO may be the same for certain areas, and that therefore you could overlap those areas in the UV, doing so would force you to use the same texture space for those areas. And you might not want that. Your design might require differences in the texture to get the look you want.

All in all, the hard part for me is UVing this so that it's all to scale. I can't stand having to scale textures to match adjacent ones.

use renderhjs uv tools if your using max does it for you in a click or two

and yes you may want different texture, depending on the object, but say each upright was rusty metal for example, i would just make one and then rotate that peice 4 times 2 at the very most

jocose

Thanks for the replies everyone. That really helps. Next time I tackle a project like this I'm sure it will go much faster.

Rens: Xtra thanks for the image!