Trim sheet with different materials on it?

jordank95

I know theres trim sheets in scifi with just normal details on the trim sheet like vents and lines, etc. Then that trim sheet gets blended with a tiling material. All great cause it retains texel density by using the tiling material. 

But I've also seen trim sheets with multiple kinds of materials on the trim sheet...like rubber, mesh, metal...all on one trim sheet. Is there a trick for this to retain the correct texel density since you can't really blend this with a tiling material? Unless theres another technique Im unaware of for trim sheets with multiple materials on them?

PolyHertz

Use masks to isolate the parts you want to blend with different tiling materials. If you just want 2 materials you could store the mask in the alpha, else you can make a separate material where the R, G, and B channels are each unique masks.

jordank95

PolyHertz said:

Use masks to isolate the parts you want to blend with different tiling materials. 

Ah, right. That makes sense. A couple questions...then why would the multi material trim sheet already have the material applied to each section for metal/rubber whatever else? Or is this done just for display purposed on portfolios?

PolyHertz said:

If you just want 2 materials you could store the mask in the alpha, else you can make a separate material where the R, G, and B channels are each unique masks.

Right, I get it now. The trim sheet material would have the normal information, then in the alpha channel a mask to differentiate both the metal/rubber materials. If its more than 2 materials, then a separate mask texture would need to made and information stored in RGB channels, correct?

sprunghunt

jordank95 said:

PolyHertz said:

Use masks to isolate the parts you want to blend with different tiling materials. 

Ah, right. That makes sense. A couple questions...then why would the multi material trim sheet already have the material applied to each section for metal/rubber whatever else? Or is this done just for display purposed on portfolios?

PolyHertz said:

If you just want 2 materials you could store the mask in the alpha, else you can make a separate material where the R, G, and B channels are each unique masks.

Right, I get it now. The trim sheet material would have the normal information, then in the alpha channel a mask to differentiate both the metal/rubber materials. If its more than 2 materials, then a separate mask texture would need to made and information stored in RGB channels, correct?

I am using trim sheets on my current project and I have done this exact thing a few times. 

2 channels actually gives you 3 materials in total. Because you don't need to mask the material that's on the 'bottom'. So you can have a base material made of steel and then paint, and rubber, layers on top. 

You can also use one of the channels to store a ambient occlusion bake for more convincing details. 

Using trim sheets isn't really a materials concept. It's a way of repeating textures and geometry to make it easier to make different objects. 

jordank95

sprunghunt said: 2 channels actually gives you 3 materials in total. Because you don't need to mask the material that's on the 'bottom'. So you can have a base material made of steel and then paint, and rubber, layers on top. 

You can also use one of the channels to store a ambient occlusion bake for more convincing details. 

Using trim sheets isn't really a materials concept. It's a way of repeating textures and geometry to make it easier to make different objects. 

Maybe Im misunderstanding a little bit. If the trim sheet base material itself is metal (even though not everything is supposed to be metal), adding a mask to the alpha channel would only give me a black and white mask option...so I can only mask out what would be the second material. I think Im a little confused how you would get 3 materials? Sorry if this is confusing me, I appreciate the help!

PolyHertz

He's just saying:

0 masks = 1 material
1 mask = 2 materials
2 masks = 3 materials
etc.

jordank95

PolyHertz said:

He's just saying:

0 masks = 1 material
1 mask = 2 materials
2 masks = 3 materials
etc.

Ok, got it now. So if its a trim sheet thats just utilizing 2 materials, that mask can just be stored in the alpha. But if its a trim sheet that has 3 or 4 different materials, that needs to be broken down into a separate RGB mask (R-metal, B-rubber, G-plastic) for example. Correct?

So are all trim sheets doing this that have multiple materials on them? Whats the harm in just applying different materials to your trim sheet texture and not using masks at all? Assuming its a texel density issue if the trim is being applied to things of all different sizes, right? What if the trim is only being applied to things all of the same size...then no masks needed?

sprunghunt

jordank95 said:

PolyHertz said:

He's just saying:

0 masks = 1 material
1 mask = 2 materials
2 masks = 3 materials
etc.

Ok, got it now. So if its a trim sheet thats just utilizing 2 materials, that mask can just be stored in the alpha. But if its a trim sheet that has 3 or 4 different materials, that needs to be broken down into a separate RGB mask (R-metal, B-rubber, G-plastic) for example. Correct?

So are all trim sheets doing this that have multiple materials on them? Whats the harm in just applying different materials to your trim sheet texture and not using masks at all? Assuming its a texel density issue if the trim is being applied to things of all different sizes, right? What if the trim is only being applied to things all of the same size...then no masks needed?

Yes - as I said trim sheets are a way of re-using UV layouts. You can have a trim sheet that has only one material and no masks or sub materials.  Trim sheets were used before it was common to have blended materials.