High Poly Normal Mapping

#1

This model isn’t ready for high poly modeling yet but I’d like to have an answer for when I’m ready.
Image

I have this model and its going to be a game asset that I will import into Unity when I’m done. What you see is the low poly version of the model. I want to create a high poly model and normal map it to this one. I have a basic understanding of how this is done, and I have a lot of resources to learn more.

Image

However, and this is my issue, none of them cover whether or not you can map multiple high poly objects onto one low poly. For example, in the depression I want to have a bunch of pistons. These would be cylinders and easier to make as separate objects. Do I have to put those cylinders into the low poly model if I want them to map correctly? Or is it ok to keep the low poly model one mesh and just mimic the surfaces of cylinders?

Thanks!
Peter

#2

If you bake the pistons into the first low poly’s cavity as a texture then they won’t have any depth.

I don’t really get the the question to be honest but what I would do to this is: Create the pistons fiirst as low poly too, then uv unwrapp them, then attatch both objects and put a unwrapp uvw modifier to it, then sepparate the uvs of each so that they aren’t one on top of the other but still in the same uv space. Afterwards, collapse it, and separate each object and start working on the high poly models for each separately, then bake them on to each separately ( both the same resolution) and combine both textures in photoshop ( gimp/etc.) and save that as the normal map. This way you can have both objects use the same texture/material and you could join them later. If you need me to clarify or help you with something else just ask.

Good luck,
-Andres

#3

No that’s perfect. I don’t know how to do all that, but I’m fairly confident in my abilities to learn from google so I can figure it out. Thank you!

#4

Hello Destructiv,
Simple answer is yes, you can bake multiple objects to a single object’s normal map.

And I think the perfect thing for you is Parallax mapping.
It uses the same image as a normal map, just rendered more ...intelligently by the game engine.

Since its a depression, and the player will not be able to see across the model, but only look down into the 'hole' I would definitely suggest using a parallax map as the rods sticking up will be just a texture, but as you rotate around looking into the hole you would never know :D

I can't tell for sure, but it looks like you're using Maya.
In Maya, you can go to the Render menu > Lighting/Shading > Transfer Maps...

The Transfer Maps tool is pretty easy to use if you haven't before.
top section is for your Target mesh or low poly mesh. Just select your low poly model of your basin or depressed surface and click add target.
The next section is for your high poly source mesh or meshes. Select each mesh you want to be baked into the normal map and hit add source on each one.

Then click the normal map out of the selection, adjust the size and what not. There are plenty of tuts on youtube about this if you want more specifics on the mental ray settings and what not, but make sure you either know where you're saving the image to, or go ahead and click the attach to shader check box. When its done you can go look at the file where you saved it or you can see the results of the normal map on your model if you change to high quality rendering in textured mode. You can see it used as a parallax map in maya as well, but you have to set up a mental ray shader to do it. Easy stuff though, and again on youtube :)

Anyway, in Unity choose the parallax specular shader or the like and you're golden.

Hope this helps, Cheers!
 - Bergquist
#5

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