Author Topic: How do you bake normal map with cylinder model?  (Read 8624 times)

 Hello.

 I Have a problem with baking normal map when it comes to a cylinder type model. Here are some images to explain what this is about.

 Above one looks decent to me but when the camera's position changes like below one, wavy line shows on the edge. That means, I suppose, the normal map has not been created by right way. I know this issue belongs to general CG theory so I apologize to ask here.

 And I know one of solutions. That is an editing cage in external application. But sometimes doing that is pain to me so I want to know if there is a way how I can get clean and nice normal map in SP or SD baker without custom cage.

Thank you very much.
Last Edit: February 11, 2017, 03:29:55 pm

No, there is no solution to this, it's a direct unavoidable consequence of mapping a highly detailed, refined model to a lower resolution model.
It will only ever look good from one angle. In your first image, it looks good from the angle of the averaged normal at the edge.

There's people straightening the normals in texture, or - as you said - people who edit the cage.
The result of this it it will look great directly  from the side, but will produce similar issues from all other angles(incl the one thats working fine in your first image).
 
The angle that's working for you in your first image, is arguably the most important one for any 'free' asset(unlike a weapon, that is hold in a specific angle towards the camera). It displays like the highpoly, despite having fewer segments.

Unless you see the model from a certain, specific angle all or most of the time, such as a weapon model, there's no point in changing anything here.

If you only ever see the asset from the angle in the second image, then it is justified to change the cage accordingly and there's no option in Painter or Designer to do that work for you.
Last Edit: February 11, 2017, 04:29:44 pm

Indeed, this issue is unavoidable. But I think the issue in general is that normal maps are abused to simulate edge detail. I do the same, everyone does, because of hardware limitations.

There will be a time in the (not too distant) future where all edge detail (such as chamfers, fillets) will be modelled into the geometry because you can. Normal maps will only be used for fine surface detail. Until that time, you have to accept  rendering errors from a too crude approximation.

No, there is no solution to this, it's a direct unavoidable consequence of mapping a highly detailed, refined model to a lower resolution model.
It will only ever look good from one angle. In your first image, it looks good from the angle of the averaged normal at the edge.

There's people straightening the normals in texture, or - as you said - people who edit the cage.
The result of this it it will look great directly  from the side, but will produce similar issues from all other angles(incl the one thats working fine in your first image).
 
The angle that's working for you in your first image, is arguably the most important one for any 'free' asset(unlike a weapon, that is hold in a specific angle towards the camera). It displays like the highpoly, despite having fewer segments.

Unless you see the model from a certain, specific angle all or most of the time, such as a weapon model, there's no point in changing anything here.

If you only ever see the asset from the angle in the second image, then it is justified to change the cage accordingly and there's no option in Painter or Designer to do that work for you.

 Hi~

 Thank you for your kind explanation. As you said, a way how I bake normal map must be implemented by the render mesh's usage and I agree with that. If I'm working with top down style project like Diablo3, I'd go for like the 1st image's way.

 But I have been always eager to know of perfect method for baking normal with cylinder model in case I'm working for various projects. In most case, I think, small props tend to be placed along with no certain camera angle.

 That's all right any way. I'm going to keep in my mind what you taught for flexible work flow. Thank you.

Indeed, this issue is unavoidable. But I think the issue in general is that normal maps are abused to simulate edge detail. I do the same, everyone does, because of hardware limitations.

There will be a time in the (not too distant) future where all edge detail (such as chamfers, fillets) will be modelled into the geometry because you can. Normal maps will only be used for fine surface detail. Until that time, you have to accept  rendering errors from a too crude approximation.

 Hello~

 Yes! I hope someday I will be able to escape from all the technical problems thanks to very enhanced hardware and I really hope that the day when normal map plays for only surface detail will come soon. Thank you very much.

Actually there is a pretty simple way to avoid the "arching" artifact.

https://www.youtube.com/watch?v=MnuK6xyi-qY&t=227s

Check out this video. The guy there is baking the high poly mesh to a subdivided low poly which follows the surface of the high poly more closely and then applies the baked map to the non-subdivided low poly and the arching is completely gone.