First Time Poster - Noob Question - Should I UV tile multiple objects together or separate?

papalati

I am finally working on my first 3D game with 3D models and I was wondering if I should put multiple objects UVs on the same texture or should I create a separate texture for each object. 

For example: 
If I have several objects for debris: planks of wood, bricks, canisters, crates, etc... should I try to squeeze all of these on the same texture. The same goes for wall of buildings and windows etc. 

I'm just concerned that some of my models will have more texel density than others if I start to cram as many objects into the same texture than other objects with dedicated textures and things will look awkward in-game. 

Any clarity on this would be of great help

Thanks!

throttlekitty

Generally you want to keep textures separate, at least for props. Sometimes it might make more sense for modular building parts to share textures, but it depends on how you'll be using them. For things like the props you mention, say you have two scenes: a city and a forest and you chose a 2k map for a crammed prop texture. You'd probably be using the props all over in the city scene. But in the forest you've only used one of the props, so now this 2k map is in memory for what might be a very small object that could have had its own smaller texture.

Sacrificing texel density just for the sake of having less textures when there's no reason to? Naaah. Also, lets say you decide later that you want some alternate crates, like one is painted red, or looks like it was burned. If the crate was single, it would be more efficient and easier to manage.

papalati

Thanks for the feedback!

I'm self-taught, and it is hard to find a full on workflow/pipeline tutorial covering every little aspect and so I was a bit confused on this transitional part. 

Yeah, from what I understood so far, better to load many selective smaller textures instead of large textures for the optimization, but wanted to make sure. I kept thinking how am I going to have a nice clean barrel and then a rusty one if it is on the same texture as a several other objects... for example.

Thanks again!

m4dcow

I would add an exception to consider that if you have objects that mostly appear together it would be okay to atlas. I'm thinking like objects one might use to make up generic debris piles, or like different ground plants/grasses etc...

Also, if you have things that don't work very well being unwrapped on their own like a plank of wood is very long, you might as well do a few variations to fill it out, maybe put stuff like nails onto that same sheet too. Then you can make  different different groupings of these objects, and each is drawcall*1, because they share the same texture and shader whereas if you have these same models, each with their own texture sheet, your number of drawcalls increases.

papalati

If I am taking each individual object into Substance Painter and painting each one, that sounds like that would be super complicated to do each object that belongs on one texture map. Wouldn't I have to take all the maps for each object and merge them for each channel in like photoshop. That seems like a super pain in the ass... that or I'm way over complicating it. 

throttlekitty

papalati said:

If I am taking each individual object into Substance Painter and painting each one, that sounds like that would be super complicated to do each object that belongs on one texture map. Wouldn't I have to take all the maps for each object and merge them for each channel in like photoshop. That seems like a super pain in the ass... that or I'm way over complicating it. 

In that situation, you'd want to export those objects together to Painter, with a single material applied to the whole set. Note that this is not all models merged into one, just exporting a selection. YMMV with other apps, but this works from Maya.

For baking, you can change the Match By behavior to each submesh. This prevents objects that might sit too close from interfering with each other. You can use an ID map baked from material or vertex color to mask off each material as needed.

I find this is much easier than doing the long workaround of exporting masks and combining everything in Photoshop or Designer.

papalati

Thanks throttlekitty, that is actually working pretty good for me!