Texture sizes and performance

[heliobyte]

I was just curious, does having parts with big textures (2048x or 4096x) have any significant impact on game performance? I.e does it cause lag or slow down the game in any way? I am by no mean a computer wizz, but as far as I understand it, having parts with big textures would mostly affect RAM. 

The reason why I ask is that I am modeling a few different real rockets, and I want decals and logos on the tanks and fairings to come out crisp and high resolution. A 1024x texture map does a nice job at it, but I'd much rather have 2048x or even 4096x texture maps to really get the logos looking sharp. 

As an example, let's say I used 4096x texture maps for 2 fairings, 1 interstage and 1 fuel tank, would that be an issue, other than just increasing RAM usage?

Thanks

 

[Van Disaster]

If you just want logos crisp, then make sure the geometry for the areas with logos has some discrete quads and map those areas at higher resolution. I can't comment on the performance impact of 4k textures but for KSP's detail levels I can't see a need for external models. IVA is a little different.

[NecroBones]

 

My understanding is that texture size has little to no impact on performance (though I could see memory bandwidth being an issue if you were using absurdly large textures for some reason). The biggest impact is the number of draw calls (with triangle count being a distant second to this), and every separate mesh object will create an additional draw call. So how these two relate, is that if you have lots of small separate textures, you would need multiple mesh objects to make use of them, which could be performance impacting.

 

EDIT: 2k or 4k is probably fine. A lot of KSP's internal assets are bundled into large "atlas" textures, as far as I know, for efficiency.

[CobaltWolf]

19 hours ago, Van Disaster said:

If you just want logos crisp, then make sure the geometry for the areas with logos has some discrete quads and map those areas at higher resolution. I can't comment on the performance impact of 4k textures but for KSP's detail levels I can't see a need for external models. IVA is a little different.

^ unwrap the logo areas as separate UV islands and blow those up on the texture, and keep the rest at a lower texel density. I usually go for something like 1k for a whole rocket but my mod sacrifices a bit of fidelity to balance the sheer size of it.

[heliobyte]

7 minutes ago, NecroBones said:

 

The biggest impact is the number of draw calls (with triangle count being a distant second to this), and every separate mesh object will create an additional draw call. So how these two relate, is that if you have lots of small separate textures, you would need multiple mesh objects to make use of them, which could be performance impacting.

 

10 minutes ago, CobaltWolf said:

^ unwrap the logo areas as separate UV islands and blow those up on the texture, and keep the rest at a lower texel density. I usually go for something like 1k for a whole rocket but my mod sacrifices a bit of fidelity to balance the sheer size of it.

I always make it my mission to never have meshes parented under the main mesh. I see some people who parent all their details such as bolts, cables, fuel lines, etc to the main mesh, instead of simply joining them together. The only time I ever parent one mesh to another is for engines (nozzle, acutators, pistons). 

With the amount of logos I want on my fairings, fuel tanks and interstages, I don't really want to have separate quad meshes for the logos parented under the main models. I'd much rather use a larger texture map to fit the main model and details, and still have everything looking really sharp. So if using 2k and 4k texture maps has no significant impact on performance, i.e  when launching the rocket, then I'll go for those texture sizes.

[NecroBones]

 

Yeah, I think you'll be fine. As an anecdotal example, if you want to look at Real Scale Boosters, I use some pretty big textures (because they're big parts). So far the performance seems good.

[liquidhype]

15 minutes ago, NecroBones said:

 

Yeah, I think you'll be fine. As an anecdotal example, if you want to look at Real Scale Boosters, I use some pretty big textures (because they're big parts). So far the performance seems good.

Yea I can attest to that. I've been using RSB for quite a while and the game plays smooth as butter. It is a very well optimized pack all around.

[Van Disaster]

On 06/07/2016 at 6:53 PM, NecroBones said:

 

My understanding is that texture size has little to no impact on performance (though I could see memory bandwidth being an issue if you were using absurdly large textures for some reason). The biggest impact is the number of draw calls (with triangle count being a distant second to this), and every separate mesh object will create an additional draw call. So how these two relate, is that if you have lots of small separate textures, you would need multiple mesh objects to make use of them, which could be performance impacting.

 

EDIT: 2k or 4k is probably fine. A lot of KSP's internal assets are bundled into large "atlas" textures, as far as I know, for efficiency.

I seem to remember tri-count ( for one mesh obviously ) being practically no impact these days - I'd like an actual quote because this has come up before but I'm pretty sure there's been more than one quote. One reason I will model rivets and seams rather than use a normal map, despite the pain of unwrapping...

Parenting makes LODs easier, but we're not doing that anyway.

Regardless I'm extremely rusty so should probably be taken with a pinch of salt, and open to being corrected.