How do I set up the bakes for a Sci-Fi trimsheet?

Danielfyang · Nov 2019

I have modeled my details in Max, and set all of my details over the plane to which I want to bake the details on.

I think that the normal details are coming out barely okay, still needs a bunch of work, but specifically I don't understand how to get a proper heightmap bake. I don't quite get where to place the baked plane and what colors I'm supposed to be looking at. Are the faces that are flat and touching the baked plane supposed to be a neutral grey? I don't have any detail that is going outwards, only inwards.

Someone mentioned to me that the baking plane should be below the details for the normals, while the plane should be over the details for the height map?

The thing that would help the most I think is to understand how high people are setting the height of their trim details to capture the elements for the normal and height map.

I'm using marmoset for my bakes but I have also tried the render to texture inside of 3DS max.
I'm not too familiar with the substance painter bakes but they aren't coming out as nicely as the marmoset ones.

The ultimate intention for my trimsheet is to use parallax occlusion mapping, but my height maps make some things blurry/fuzzy.

If I could get some tips on what I am doing right/wrong that would be extremely appreciated...

Here's an example of my height map currently.

Image: https://us.v-cdn.net/5021068/uploads/editor/10/bbjppar3ymc6.jpg

The completely black spots are going to be alpha'd out like metal grating

Here's the Normal map:

Image: https://us.v-cdn.net/5021068/uploads/editor/4a/9uo3fxijj9dg.jpg

Here's the setup in Max for my placing the planes and the details

Image: https://us.v-cdn.net/5021068/uploads/editor/aa/rklwuwzsjka4.png

sprunghunt · Nov 2019

Very few games would use a height map or parralax occlusion for this kind of geometry. It's not usually worth the cost.

icegodofhungary · Nov 2019

You shouldn't have to move your plane for baking a height vs normal, unless there's something I'm unaware of. Your height map is just black at the lowest point, and white at the highest (and neutral gray in the middle). If you're looking at value/brightness, 0 at lowest, 1 at highest, 0.5 at middle. If you want RGB, 255,255,255 at highest, 0,0,0, at lowest, 127,127,127 at middle. But don't fret over this the baking program will take care of values for you. You actually don't have to use the full range of values, it depends on what you're making. So your lowest point could be gray rather than black, and your highest gray instead of white. Placing your plane at the highest point vs the lowest doesn't change anything. The baking program would still assign white to be the highest, and black to be the lowest.

The thing you would want to avoid is placing your plane so that it cuts your geometry the wrong way. For example, if your high poly is a strip of metal with inset detail, you want the lowest point of that strip to be above the plane you're baking to. Otherwise the computer won't pick up the detail that falls below the plane (unless you set a cage or something). If for some reason you couldn't set the plane below the lowest detail on that strip, you could, alternatively, set it to the highest point of the detail and then the computer would just work backwards. I can illustrate this if need be, it's kind of hard to put into words. Basically your plane should be lower than your lowest detail, or flush with the highest detail. Anywhere in the middle and you run the risk of slicing off detail in your bake, and you'd have to fix it by making a cage or changing the ranges of the bake.

That being said, unless you're using height blending to create dirt/mud/moss/water puddles/etc, you don't need a height map for a normal trim texture. As sprunghunt said, games don't use parallax in this way. This is the downside of all those neat Substance balls people make. They look great in Substance when you have a bunch of tessellation and parallax, but it's not something used in games. Always make your normals to look good on a flat plane, and to be used in a standard PBR texture.

If it makes you feel better, your normal looks fine to me. I would suggest importing it to your engine or renderer and seeing how it looks on actual geometry. It's going to look a little flat to you, but don't let that discourage you. Remember that most of this stuff will be passed by a moving player, and not dwelled on too long.

Danielfyang · Nov 2019

Thanks for the replies guys!

@icegodofhungary I really appreciate that in depth response!

Your illustration makes perfect sense, it's just really annoying to get such drastically different results from different bakers, and I'm not sure how to get the optimal scenario where the top of the high res is white(the highest point) and the deepest points to be the dark gray.

To give more background, I am trying to replicate some of the Star Citizen techniques and I guess it kind of makes sense to not use trims like this for POM. Would it be ideal to use a decal sheet with individual hard surface details and cut out the plane to be placed right above my mesh instead? I would use them as a deferred decal instead in UE4.

icegodofhungary · Nov 2019

If you're using the SC technique, I would just make a series of tiling grate textures and use those on planes, rather than a trim sheet with 5 different grate textures. Make maybe 3 tiling grate textures and come up with some other ways to create variety, like the geometry around the grates, decals, and using them in combination with other tiling textures. Like a grate surrounded by concrete, and the same grate surrounded by metal. Maybe one with another plane below the grate with some wires or technical doo dads on it.

xNormal lets you adjust the range of the height map when you bake it, I'm sure marmoset has a similar option, but I don't know where to find it as I don't use marmoset. You might be able to open it up in photoshop and adjust the curve to give more range as well.

Danielfyang · Nov 2019

Alright, thanks so much for your time! I'll make changes accordingly.

How do I set up the bakes for a Sci-Fi trimsheet?

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