[3ds Max] Some more annoying/rookie Unwrap questions...

Dubious_Fellow

Hi,

1. I'm working on a large model made up of 300 individual objects (a ship). Do I have to do as some tut's suggest and attach them all together before unwrapping, or can I unwrap them individually, then attach and put them all on the same texture sheet afterwards?

2. My high poly is around 16 million polys, will that be a problem for Substance Painter to handle when baking the normal (is there some sort of limit or does it all boil down to your machine's RAM)?

3. After much debate I'm going with the texture atlas method for this model (everything on one sheet). What size should I/can I make it? (its going in UE4 for an FPS/exploration hybrid). Is there such a thing as 16k/32k maps & if so does using them cause any performance issues in-game?

-thanks in advance for the on-going help!

Mark Dygert

1) You can do it either way, but there is another option. 3dsmax does let you apply unwrapUVW to a selection of objects and it lets you operate on all of them as if they where a single object, but they aren't. It applies an "instance" of unwrapUVW to each one. However it does have some issues with some of the tools. Relax and normalize tools sometimes fail to work correctly.

Personally I attach it all together and break it apart if I need to afterward. If pivot points are important (usually for animation or ease of modeling) then I snap dummies to the objects before I combine them. You might want to check scriptspot.com I know there are a few "create dummies at all objects" scripts floating around. They also have scripts that break apart the elements into their own objects.

2) That really depends on your system and the size of the maps you are outputting. Substance won't output anything over 8K and there are some hoops you have to jump through to get that.  I've feed substance meshes that dense before and rendered 4k maps and not had a problem. IF you run into problems you should look at optimizing the high poly, depending on where it is coming from there are usually a few ways to make sure you don't have an excess amount of verts.

3) Something is wrong if you're above 4k. 16k and 32k maps will certainly cause performance issues, if you think you need them you need to use separate maps or think about using tiling textures, or overlapping UV's.

Dubious_Fellow

Mark Dygert said:

3) Something is wrong if you're above 4k. 16k and 32k maps will certainly cause performance issues, if you think you need them you need to use separate maps or think about using tiling textures, or overlapping UV's.

Thanks, but now I'm really confused! My ship has rotating turrets so it sounds as though I need to attach 'dummies' to them before I attach everything together? (the dummies are the same as 'bones' used to animate in UE4?). I was going to leave them as separate objects, but put them on the same UV-sheet...?

I was thinking 32k because the ship is a couple hundred meters long and you can get up close to it in-game. I was thinking that if a small object like a gun has a 2k map, something huge like a ship would have a 32k (at least)?

-should I think about dividing the ship up into say... 3 different pieces and applying a separate 4k to each part?

Here's a pic of the high-poly so you have a better idea of what it is I'm trying to tackle (the low is 30k polys):

Mark Dygert

That is a good lookin ship!

The dummies are just place holders for the pivots. When you attach the turret to the boat it will lose it's pivot. The dummy is there for when you detach the turret and want to set it back to it's original location. Depending on your ex/import plugin, it usually has an option to convert dummies to bones. laying out the bones before you join the meshes might work too, and then just leave it all joined. 

The point is, the objects pivot is sometimes worth backing up for later.

As for the textures, you are correct in thinking that an object that size will be a challenge to maintain the texel density, but increasing the resolution isn't the only trick you have available to you, a lot can be done with tiling textures and not all of it needs to be unique pixels. 
A lot of the rigging and ropes can share a simple rope tile texture.
The lifeboats can share textures and you only really need to texture one side and mirror to the other.
The hull and decking can use tiling textures, so can many of the metal walls.

Depending on the engine you are using there are a lot of material tricks that you can do to break up repeating patterns and add in unique material details, using decals, mesh decals and vertex color/paint as a mask.

Here is a fairly decent example that will probably give you a few ideas. 
https://free3d.com/3d-model/lcac-27-82860.html

X-One

Mark has definitely got you on the right path. I really wouldn't consider the ship a single model. If you're camera/player is ever going to be on the deck of the ship, I really feel like you should be treating the ship as an environment rather than as a single asset.

 As Mark mentioned, making good use of tiling textures and overlapping UVs will go a long way.  Consider using tiling textures in conjunction with vertex paint texture blending, plus decals to break up the "tiled" look over large surfaces.

The quality of the ship looks fairly good, but I would not suggest trying to get away with unique UVs for much of it at all, unless it is only going to be viewable from a distance.

Dubious_Fellow

Mark Dygert said:

As for the textures, you are correct in thinking that an object that size will be a challenge to maintain the texel density, but increasing the resolution isn't the only trick you have available to you,

Thanks for the advice guys. Clearly my original plan of importing it en-masse into SP with unique UV's was unviable. I'll do some research on Vertex painting and brush up on tiling/decals.

I do feel bad asking more questions, but it seems like everytime one is answered, two more take its place... the thing that has me really baffled right now is the Normal and AO maps. Presumably they will use the same UV's (including tiling), but what resolution do I make them?

Just to clarify (for X-One):

-This ship is basically just a fancy target. The player isn't meant to board it (but annoying/adventurous players may be able to get onboard temporarily while its sinking?).

-It will be seen from long range. The player can then either sink it with torpedoes or get up close and place explosives on its hull.

-This model will be encountered out in the open sea, so there shouldn't be a whole heap of other models in the scene.

-I'm building an UE4 Indy game from scratch (by myself -which is why I appreciate the help so much). I feel this needs adding as some folk might just see this as some noob who's taken a paid job and is out of their depth. 

I'm really lost here. If somebody would take the role of "Virtual Art Director" I'd be eternally grateful (i.e. set some firm limits on the size and quantity of maps).

If you were tasked with making this model, what limits would you set yourself?

monster

So if you are very pressed for time and since "It will be seen from long range", you can use Blended Box Mapping to basically planar project textures onto the model. Then create a good set of UVs, and render the Blended Box Map to a texture.

https://youtu.be/s6opNuqSC5I

But if there's a chance it can become a hero asset the advice these other guys gave is better.