Multiple textures on a single scenery object

[cnwfan]

I'm working on a rather large industrial building for one of my routes. Normally, I try to keep the texture count down to one per object. However, this building is large enough with an odd shaped roof that fitting all the UV pieces on a single 2K texture is causing image detail to be lost on smaller pieces as the roof takes up about 2/3 of the texture. I thought about a single 4K texture, but I'm wondering if two 2K textures (1 for the roof, 1 for the rest of the building) would be a better alternative. This building is trackside, and I'd like some level of detail to the building and the textures.

I know 2 textures (or more) can be done on a single object as I've seen it on various locomotive objects. I'm just not sure how to set it up in Blender or get it exported out using the Briage exporter. And, baking out 2 texture images. I'm using mostly asset based procedural materials in Blender along with some image based asset materials. Any pointers / advice would be appreciated. Thanks!

[cnwfan]

The below may just seem like a simple 2x2 meter box to some, but this is a major milestone for me. After much fiddling and a substantial amount of frustration, I either figured it out (or stumbled upon) getting two textures mapped to single object. The brick work is one texture, and the roof is a separate texture. All along my thinking had been object based... how do I get multiple texture images to output on a single Blender object. But after looking deeper into the Briage exporter it finally clicked. I can export multiple Blender objects to a single .igs file as long as all the objects are in a single visible collection. I just need to make sure that all objects have a single material assigned to the object that is defined in the Briage settings. From a modeling standpoint, it will mean multiple collections in a Blender file, especially if I need to bake out multiple object textures to a single texture (I'm using the Auto Bake add-on).

As for the industrial building that started this week long endeavor, it will need to be reworked for the above workflow. But, for those large trackside buildings where a higher level of texture detail is needed, I'm glad I now have the option to go multiple textures. Yes, I know there may be slight performance hits as I'm calling an extra texture off of the disk and into memory. But with today's CPU's / GPU's, and if a multiple texture solution is limited to only certain scenery objects, I think it will be worth it to get that extra level of detail that we might not have been able to achieve a decade ago. I'll post a screen shot of the final industrial building once it's completed.

20260114222322_1.jpg

[GreatNortherner]

Hi Howard,

Figuring out such "small steps" which really are personal milestones is where I always think half the fun is in learning and exploring things.

Roof surfaces are an ideal candidate for tiled textures. That way, you can cover a huge area with something as small as a 256*256 or 512*512 texture, thus saving vast amounts of texture file size and clawing back some of the performance hit of the extra draw call. The RW IGS format also allows combining tiled textures in the primary slot with a non-tiled AO map in the second slot if you'd like to add some AO shadows around chimneys or similar and still use the tiled texture (though I don't know how that works in Blender, but I'm quite sure I've seen it done on some models).

Cheers,
Michael