Static mesh made from multiple elements.

knak47

When making static meshes in Max to be imported into UDK, is there any draw backs or benefits to creating a mesh out of multiple elements, aside from polycount. Do people generally try and keep there meshes solid? I know animated meshes should be one element. But meshes that aren't going to be deformed, are there pros and cons? I am specifically wondering about lighting issues.

odd_enough

First off, I wouldn't say that animated meshes should be one element. This is more true for character meshes, but even that isn't a general rule. For animated environment props and weapons, having a multi-element mesh is a very good idea. Floating geometry involving mechanical animation is optimal (especially from an absolute weighting standpoint where you don't want deformations to occur).

But back to your original question, as for drawbacks, really the only drawbacks I've found from doing that have been lightmapping issues, for continuity reasons. Breaks in geometry create seams in the lightmap UV's. Unless these seams land on areas on the model that have a baked in AO, or are covered up in other ways, it could look funky. Other than that, I don't see any drawbacks to this. Delete the faces of the elements that cannot be seen by the player, if there are any, to save on poly count.

I'm also curious to know if anyone has found any other drawbacks to this method, as I've only been doing this for ~8 months and still have plenty to learn.

sprunghunt

it can create lightmap issues - see the example with the crate here:

http://udn.epicgames.com/Three/LightMapUnwrapping.html

also making objects out of multiple materials can be a performance problem.

knak47

So how are these Lighting issues generally avoided, there must be some settings within UDK becasue it is only an issue with lightmass and the inderect light that hits an object? Often it makes no sense to model something out of one consistent mesh. For instance if someone wanted to use a workflow similar to Racer445's in his tutorial for CGTuts Plus found here http://cg.tutsplus.com/tag/racer445/

sprunghunt

knak47 wrote: »

So how are these Lighting issues generally avoided, there must be some settings within UDK becasue it is only an issue with lightmass and the inderect light that hits an object? Often it makes no sense to model something out of one consistent mesh. For instance if someone wanted to use a workflow similar to Racer445's in his tutorial for CGTuts Plus found here http://cg.tutsplus.com/tag/racer445/

There aren't any special settings you use to avoid this. Careful attention to construction of meshes and uv layout is what helps.