Normal Map questions
polycounter lvl 11
Hello everyone,
as some of you may know I am pretty new to game modeling and I am currently starting to explore normal mapping in both theory and practice.
As for theorie I read stuff on numerous forums, websites, wikis and so on. So I am not fully "Normal Map 101", but some questions I just can't answer myself or I simply don't understand some things. So I decided to let you guys help me answer those questions explicitly, this doesn't only help me but also other newcomers to this topic maybe. So if there are any more newbie to this topic feel free to throw in some questions also! Would be cool if you guys could answer my questions in an easy and step by step manner as if you would tell them to a newbie or someone which isn't very deep into the topic (me
I also know that all situations and workflows depend so if there is a case where it's up to the situation it would be cool if you could state some examples.
Questions:
1. Cage baking 101: How exactly does a cage work? How to setup a cage correctly instead of just using the "push" value?
2. What's the difference between using cages (e.g. projection modifier in max) and no cage (baking via offset value)? Advantages/Disadvantages?
3. The miracle question which although I tried to answer for several hours I am still not fully sure about: When to bevel edges and when to use smoothing groups? Advantages/Disadvantages?
4. What causes waviness in normal maps and how can it be fixed? (I know there are several posts about that by EQ, but I don't really understand them as they are written for people who already are deeper into the topic than I am *shame*)
I think that's it so far. I thank you guys for your time! I appreciate it very much!
as some of you may know I am pretty new to game modeling and I am currently starting to explore normal mapping in both theory and practice.
As for theorie I read stuff on numerous forums, websites, wikis and so on. So I am not fully "Normal Map 101", but some questions I just can't answer myself or I simply don't understand some things. So I decided to let you guys help me answer those questions explicitly, this doesn't only help me but also other newcomers to this topic maybe. So if there are any more newbie to this topic feel free to throw in some questions also! Would be cool if you guys could answer my questions in an easy and step by step manner as if you would tell them to a newbie or someone which isn't very deep into the topic (me
I also know that all situations and workflows depend so if there is a case where it's up to the situation it would be cool if you could state some examples.Questions:
1. Cage baking 101: How exactly does a cage work? How to setup a cage correctly instead of just using the "push" value?
2. What's the difference between using cages (e.g. projection modifier in max) and no cage (baking via offset value)? Advantages/Disadvantages?
3. The miracle question which although I tried to answer for several hours I am still not fully sure about: When to bevel edges and when to use smoothing groups? Advantages/Disadvantages?
4. What causes waviness in normal maps and how can it be fixed? (I know there are several posts about that by EQ, but I don't really understand them as they are written for people who already are deeper into the topic than I am *shame*)
I think that's it so far. I thank you guys for your time! I appreciate it very much!
Replies
First, your high poly and your low poly should aquire the same exact space. Be the same size and be right on top of each other. Second, your cage should only be slightly larger to envelope both high and low, you want it to envelope each as close as possible, but still be slightly larger then both.
Cage is the best way to transfer your maps. Best accuracy and most control. Offset is just for speed and rare cases. Use the cage.
The million dollar question. A quick test bake will show you what you need to fix/bevel/smoothgroup. I usually get the objects uv's all unwrapped but NOT packed, then just do a quick auto pack, bake and take a look at the model inside whatever engine I need to use. Once in the engine, analyze what needs to be fixed(if triangles/slants are appearing in your bake) and what can be left as is(the player might not see it).
The waviness is explained in EQ's thread very detailed. LINK
Matching the low to the high using more geo(among other things like support edges) will help the waviness disappear.
2: AA cage gives the best results at the edges of the model, baking without cage gives better results for surface detail, since it is not skewed by the rays hitting the model at an angle.
Scroll all the way down to "Solving Wavy Lines". There you can see an example how the cage affects the normal map.