Blender + xNormal = normalmap issue

mjeruzal

When I was working in Max I haven't got such a problem, but now in blender i don't know what's going on I've got weird "seams" on 90 degree corners no matter if UV islands are stitched or not, and on high poly they're only beveled a little. I was using edge split modifier method, here is the result.

When I try to use model without edges splited it totally looks like shit (low poly edges on bake, gradients everywhere etc.). If you know any other method how to properly export lowpoly to xN I would be grateful.

Neox

how does your normalmap look like?

and the gradients are not a problem in general, if you have synced pipeline, however the gradients to get messy with compression so less gradients should be preferred

mjeruzal

That's how it looks right now (same map as in image above):


And this is what I get when I'm not using edge split method:

And on the model:

Seams looks ok, but as you can see (marked with red) there are some issues on flat geometry.

Neox

so you have hard edge splits but no uv splits if i see this right?

mjeruzal

Yep, but technically there is no split on flat geometries.

Also I've made mistake and put that gradiented normal map on "splitted" model... Here it's how it looks like on model I've baked it to:

Not bad i think, but there are still issues on flat geo.

It's barely visible but highlights a lot on extreme viewing/light angles.

Neox

i'm not sure what you mean by there is no split on flat geometries.
when you have a smoothingroup split you HAVE to use a uv split, you don't have to do this the other way around tho.

i can only guess but unless blender and xnormal are synched there will always be some issues, slap on a diffuse map and specular and glossiness (or metallness rougness whatevs) and the slight imperfection will be invisible.

mjeruzal

I mean that I split only edges (on the model) that are marked as sharp. And I don't know what do you mean in your second sentence
Here it is how I'm doing that:
- flatten mapping my UV and then stitching pieces
- select hard edges on the model and mark them as sharp
- apply Edge Split modifier with checked "sharp edges" and without "Edge angle" option
- export with applied modifiers to .obj

As I said it highlights on extreme viewing/light angles:

so I doubt if diffuse and specular will cover this

billymcguffin

Wherever you have a sharp edge in blender, there must also be a UV seam (but you don't need a sharp edge on every seam). Also, don't use the edge split modifier on the exported mesh (delete it before exporting). Just make sure to check "Smooth Groups" when you export as .obj (this will convert your sharp marked edges to smoothing groups and everything will work).

Frankie

did you try triangulate modifier before export to xnormal?

mjeruzal

Billy, I did everything as you said and result was the same as in the first image in this thread
Frankie, yes, model was triangulated before export.

billymcguffin

Could you post the .blend?

Have you tried using a cage? Not using one could cause projection issues and repeat details.

mjeruzal

I wasn't using the cage. Maybe I'll give a try.

I'm on my student internship in indie gamedev studio, model I'm working on is a part of project and I have no idea if I can share it here, sorry

Neox

yeah use a cage, however looking at your bakes, there are either no uvsplits or you need to make more space between your UV islands because right now it looks just as if the edges are merged.

EarthQuake

Yep, use cage, split and move your uvs at all hard edges.

More here: http://www.polycount.com/forum/showthread.php?t=81154

mjeruzal

I've changed unwrapping leaving islands separated in few last bakes but as I said result was the same

Here, I've recreated this issue on cube:
http://www30.zippyshare.com/v/56002947/file.html

And there are my lowpoly export settings:

billymcguffin

Yep, it's a projection error. Using a cage solved it for me.

Perhaps you know this but to make a cage in blender, just duplicate your lowpoly, then in edit mode press alt+s to push the mesh outwards until everything's covered, then remove sharp edges (not sure if this is necessary?) and export.

mjeruzal

It works well on cube but for some reason not on my model Does cage and model need to have splitted edges or not?

billymcguffin

As far as I know, the cage should have no sharp/split edges, although it shouldn't matter.

mjeruzal

I try with and without split edges and it's all over the same seamful result

JedTheKrampus

It's better to use fbx export for baking with XNormal, since that format can carry exported vertex normals (and in 2.71, tangents and bitangents) that XNormal can read. You shouldn't use objs to export to XNormal unless you're using ZBrush.

wheel_

FYI, blender can do per-face normals at a vertex without an edge split modifier now (as of 2.71). Set the object's shading to smooth, add sharp edges, and check "Auto Smooth" in the Mesh Data tab.

All the pre-2.71 tutorials are going to tell you to use edge split for sharp edges, but it's no longer the only way.

billymcguffin

wheel, does autosmooth still smooth by angle, or just by sharp edges?

wheel_

Still smooths by angle as well.

billymcguffin

Ah, thanks for the info!