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Normal map Problems
June 24, 2010 - 11:20am
- 3070 reads
Hi guys,
I started with this model to eventually to make it low poly so i started with 8 sided cylinder ,it works well with turbo smooth but normal map looks really bad ,any tips to work around with my existing model or do i need to create good 40 sided cylinder to come up with a decent normal map ,i tried whole night just with mapping cylinders with normal map but only 40 sided cylinder looks alright and rest of them just look bad.............pls any tips ,advice welcome ...i am trying to create portfolio ,but just get stuck with this normal map thing...
1) does cylinder need to be really rounded for normal map to work properly ,like is 8 or 12 sided cylinder bad start if i making this for game asset
2) any tips tutorials on normal maps i have gone through couple of them but most are either characters or flat planes not cylinders exactly
3) any other methods for coming up with normal maps ,i have tried same smoothing groups ,as wells same smooth for whole object but still any other tips ,technique etc
I don't really understand the images you have posted, what do they relate to?
Also you don't state whether the "40 sided cylinder" is the High poly or the Low poly? Also what are you baking it in?
Have a read through this. It has so much information in there to read about.
Hey Maxkid,
The silhouette of the LP will always dictate the shape of the object no matter what the normal map is doing so they only way to get a better shape is to add more geometry. As a rule normal maps can only represent details that are fine or recess into the surface...anything else should be added with geometry.
When deciding the number of sides you have to take into account how big the object is in relation to the player and how closely it will be viewed.
Generally i think that an oil barrel, a tyre or something around that size should have around 22 sides or so but a small wire or a piece of rebar that is less than an inch wide should have around 4 or 5 (depending on your poly budget) but in a portfolio you can get away with a little more as the point of it is to look good (just dont go crazy with 40 sides on a tyre 
)
How big is the object you are creating?
It would help if you post the normal map and LP mesh with wires so we can take a look at it and give better crit.
As for tips...
- When adding smoothing groups split your UVs in the same place and move them apart by a few pixels in UV space...this will stop the black shadowing that can happen around the edges when baking as it stops the vert normals being represented incorrectly and will also stop smoothing group seams.
- Explode your HP and LP meshes so each part is separate when you bake which will stop tracing artefacts.
- Remember that adjusting your cage can dictate how the rays are cast which will affect your final bake. (great for stopping the wavy lines on cylinder edges)
- If you cant or don't want to wait for 4xAA when baking maps turn it off and bake at double resolution and resize and unsharp mask @around 40 for the same effect. (If you want the final map to be 2k bake at 4k with AA off and then resize to 2k and sharpen).
Hope that helps 
hey there,
Thanks for answering my query ,i thought so normal map is not going to make my 8 sided look round ,i will try it with 24 or so ,remodel ,uv & tex and post it again ,Thank u very much ,Thank you for all the tips & Thank you for the link jackboy
cheers,
maxkid
I love you EAT3D
pls anybody