Combine textures (reduce draw calls)

[Nmzik]

Hello!
Immediately I apologize if I did not write the desired topic!
The problem I have is this:
I'm doing the game on the Unreal Engine. I have a model in 3ds max
It has about 8 materials
I want to optimize the model (reduce draw calls)
there is a way to connect(combine) all the textures in the same ( 1 draw call)
But that's how I did not understand
Is there such a thing called a render to texture
So I use it but I have a problems:
1) poor quality (1024x1024)
2) if I put quality at 4096x4096 it will be OK
But then the size will be about 15 MB!
That's a lot for one texture!
That is, the texture memory will be big!
Although there are eight materials weigh only 4 mb (there are a few of 512x512 and 128x128)
What you may suggest to me?
thank you

[JessieG]

I generally say go with the bigger single texture (optimizing UVs could give you good results with a 2048 texture) or cut it down to two 1024 materials at the most. 8 is far too many for anything in UDK, character or not. Use the large textures for the characters and other important parts and just watch your performance, which shouldn't be bad as long as you don't go for super high detail for EVERYTHING in the environment.

[mAlkAv!An]

What kind of model is that, character, building... ?
Go the middle way. For example put the small 128-512²px textures into a single one and make 2 additional ones with 1024-2048²px. Or go with tileable textures for some parts so you can re-use the material for multiple models.

[Nmzik]

Thank you for answers
I have a building
1)how optimize UVs?
2)how cut to two materials(textures )?
3)how to put small textures into single one?
Thanks

[mAlkAv!An]

Just give some parts of your mesh the same material ID in 3ds max. Then you scale down the UVs of each part and rearrange them to not overlap with UVs of another part and to fit in the 0-1 space.
For a building you should use tileable textures for all large areas (f.e. walls).

[darthviper107]

Depending on what your model is it might have issues--like if you need a tiled texture across a large surface you wouldn't really be able to combine that texture with others.

But--to be able to combine textures, what you'd do in 3ds Max is attach all the pieces into one object, it will ask you about the materials and material ID, you want to keep the materials, so it would then automatically assign ID's to the pieces to keep the materials on them. Then you would create a new UV channel, and in that channel you'd reorganize your UV's to fit in the 1x1 space, you cant either do it by hand, automatically pack them, or you can have it do an automatic unwrap. After that you go to Render to Texture and you set it to render to that UV channel, and what it'll do is actually render a new texture with using your new UV's, then you just create a new material with that texture and assign it to the whole thing---although you'd want to make sure to use the same UV channel for that texture, or you can copy the UV's down to the first UV channel.

If you don't understand this workflow look into Render to Texture and UV Unwrapping

[Nmzik]

Yeap I know about it)))
But my problem is that I need to render every building in 4096x4096 to have best quality and the size is about 14 mb
So it will have much texture memory!!

[darthviper107]

If it's a building then I wouldn't combine the textures---since you really do need to be able to tile those things for high quality. If you've got some textures that aren't tiled then I'd combine those ones.

[Nmzik]

ok
but in future i want to run my game on ios
So i just need reduce draw calls

[darthviper107]

It all depends on the quality you want, if you combine a texture then unless you have your tiling texture going from one side of the texture to another (so you can tile) then you wouldn't be able to tile it. Otherwise you'll have to just deal with the lower quality of the texture.