I can't bake a good normal map : Green artifacts and missing AO

kadock

Hi,

It's been a few weeks i'm struggling with normal map baking and i'm asking for help because i ran out of solutions.

I'm  creating a simple barrel. I just turbosmoothed my low poly and i'm trying to get a good normal map out of this.

There are 2 cases:

1. The wood and the metal meshes are seperated : my normal map looks weird on the edges and the AO  is missing between the two meshes

2. The wood and the metal meshes are one single mesh : my normal map looks weird

I made a mistake, but I don't know where...

If somebody can take some time to help me I would be very grateful!

Thanks!

icegodofhungary

You need a cage file to get better renders on cylinders. This would be something with the same topology as the low poly, but "inflated" to encapsulate both the high and low poly meshes. I wouldn't even auto-generate one in this case, make it by hand.  It will also help to change the highpoly's bands to be slightly beveled. Bakers *hate* right angles. So when you extrude the bands, make sure to scale the faces down a little on the vertical axis so there's an angle to their sides rather than right angles. I can't exactly see how sharp your edges are in the highpoly, but always err on the softer side of edges. This helps with baking and is a good habit to get into for when you start having to deal with LODs. Your high poly should have slightly softer edges than you think you need.

Check out these resources:

https://www.youtube.com/watch?v=MnuK6xyi-qY

https://www.youtube.com/watch?v=qefbyHVqgpk

https://polycount.com/discussion/81154/understanding-averaged-normals-and-ray-projection-who-put-waviness-in-my-normal-map/p1

kadock

Thanks for your advices and the videos, it helped me a lot but i still have some trouble. I spent my day trying to make my normal map work but i can't get better result for the three bands :

In case N°1, I turbosmoothed my low poly to create a normal map that i applied on my low poly, as shown in the first video -> my mesh doesn't look smoothed.

In case N°2, I baked directly my low poly without changing it -> I get artifacts on the edges

I can send a screenshot of anything else if needed.

If anyone have an suggestion please let me know, and thanks again Icegodofhungary for your time!

Joopson

I think you're expecting too much out of your normal map. It can't make up entirely for really low geometry, and it can't look perfect from every angle.

Remember, a normal map is essentially faking shading based on the projection angle of the rays. So, any angles far outside of the ray projection angle can still look really weird or wrong, or just wonky. Which is why adding more geometry, if you can afford it, can solve a lot of baking problems.

icegodofhungary

Yeah it's really all about 1) how much screen space will this take up? this includes how close the camera will get to it, and, 2) what angles will this be viewed from? If it's a physics object that gets thrown around and seen from all over, you should increase your geometry (add sides) to the cylinder. If you're sticking to some budget, then maybe re-think the design. Rather than using geometry for the bands, just bake them down into the normal itself, This would get rid of that rim where you're getting problems. And then just use really solid texturing work to add to the illusion (this is were those non-90 angles I mentioned would come in).

You could spend a lot of time carefully baking and tweaking but you don't want to spend days working on an object that's not too important in your scene. If you're just trying to learn baking and high-poly modeling, start with a plain cylinder and learn to bake that perfectly. Experiment with adding and removing geometry to see what works. Watch and read as much as you can, there's lots out there about baking normals. Even read the older stuff. Then move onto more complex objects like a barrel and then a gun or some piece of technology with cylinders.

rollin

+1 for bake AO and normals from 2 different models if that turns out to be the best workaround

kadock

Thanks to you Joopson, icegodofhungary and rollin for your help ! I will practice on my own and see what works!

Have a good day to all three of you!

SuperFranky

You might be interested in checking out my normal mapping guide. The link is in my signature.