Quick Xnormal question

26708

Hello, I just started trying to make models recently this summer and I'm finally on the 'baking' step of the workflow for my first model. 
I'm having this issue where my UV maps and height maps are coming out a bit weird.



If someone could help me understand why these hard edges are occurring and a potential solution I'd be really grateful.

Thanks!

Bek

Your lowpoly and/or cage must be reading as all hard edges. Check it in the xNormal 3d viewer. Either it's been exported that way, or you've mistakenly set "harden normals" or whatever the phrasing used in xN is under the mesh list. (you'd want use exported normals, assuming you've exported the mesh with the correct smoothing)

26708

Bek said:

Your lowpoly and/or cage must be reading as all hard edges. Check it in the xNormal 3d viewer. Either it's been exported that way, or you've mistakenly set "harden normals" or whatever the phrasing used in xN is under the mesh list. (you'd want use exported normals, assuming you've exported the mesh with the correct smoothing)

Hi, thanks for the reply.
This is how it looks like in the xNormal 3d viewer

I used the exported normals option and every other option but it still came out like it did in my previous post. 
I'm guessing then that I had to export the mesh with 'correct smoothing'? How do you do that exactly?
PS: I did not use a cage since the tutorial I was following didn't use one as well.

Bek

Well that depends on your 3d software. Check its export options. For a tangent-space normal map you need to bake with the same smoothing as the final mesh will have. The polycount wiki can give you an explanation as to why.

26708

Bek said:

Well that depends on your 3d software. Check its export options. For a tangent-space normal map you need to bake with the same smoothing as the final mesh will have. The polycount wiki can give you an explanation as to why.

I'm currently using Maya. 

So I've googled and went to meshdisplay/normals > soften edges as well as set the smooth normals option on when exporting as a .sbm file.

The UV maps are coming out fine now, but the height maps still have these really hard edges.

Is this normal? I'm assuming it isnt for a height map to also show up this way. 
Would this be solved if I used a cage? or am I yet again just missing something.

CheeseOnToast

The height map is correct. It's measuring the difference in height between the lowpoly and the high. It doesn't care if normals are soft or hard.

pior

Indeed, if you want a heightmap later used for displacement you will need a new version of your "low" subdivided up to a point where one polygon is roughly the size of one of your target pixels. Here probably something like 3 or 4 levels.

(Also don't bake your normalmap with only one half of your lowpoly, this is a recipe for disaster. Make sure that your low is complete geo wise (with verts correctly welded down the middle line), and move one half of your UVs out of UV 1-1 range).

26708

pior said:

Indeed, if you want a heightmap later used for displacement you will need a new version of your "low" subdivided up to a point where one polygon is roughly the size of one of your target pixels. Here probably something like 3 or 4 levels.

(Also don't bake your normalmap with only one half of your lowpoly, this is a recipe for disaster. Make sure that your low is complete geo wise (with verts correctly welded down the middle line), and move one half of your UVs out of UV 1-1 range).

So if I want to use the height map, I just need to smooth it with 3 or 4 additional subdivision levels, and use that more 'high res' low poly model as the basis of the height map? And that new height map will still work with the original low? 

pior

Well it depends what you want to do with it of course. If your goal is to use it, well, like a heigth/displacement map then yes that's the way to go, because offline displaced renders do rely on subdivision. Now for realtime uses I suppose it may vary since all engines are different (for instance in Toolbag displacement only modifies the silhouette but does not create any surface shading).

It's up to you to define why you need a height map in the first place and what you are using it for. I would assume that if you are going through the trouble of rendering it, then you probably already have precise use planned for it !

26708

I was actually just mindlessly following a tutorial since the tutorial said to just use it lol. But for my purposes turns out I don't need one.

Thanks for the help everyone. 
I'm sure i'll be back with another question soon lol