Normal Map Problems

waffles.c · Dec 2013

Hey fellow peoples of poly count. I have run into some problems regarding a sword I am making.

heres the sketchfab for it:
https://sketchfab.com/show/fe4e65972ced4a3cbea5bc8113d4d5c0

Im getting weird "Black spots" on the edges of the middle part of my sword (check out the sketchfab and youll see.)

Attached is the normal map (ive circled what i think are possible problem areas)

Any help would be much appreciated. Thanks!!

jamesman5000 · Dec 2013

it seems like it's a problem to do with your faces I'm probably wrong tho how did you make your normal map?

AlecMoody · Dec 2013

There are several issues on here. Post an image of your highpoly model overlapping your low so we can see better.

It looks like there are projection issues on the bottom left area of this image (inside the hand guard area):
http://gyazo.com/0fa7c4baeab1ddc865933f1fa54f2ca5.png

The lighting errors across the hand guard are tangent basis or triangulation related (or both). Either way, evaluating shading errors in an engine other than your final target engine isn't particularly useful. Are you triangulating the model before baking?

belkun · Dec 2013

Did you use a cage? If not, I'd recommend you to do so. Still, there's no real need to bake it again, you can easily fix this on Photoshop with a quick paint over or just using the Patch Tool. I'd also recommend you to mirror the UVs, since both the blade and the hilt don't need separate textures, as you're not going to be able to see both sides at the same time.

waffles.c · Dec 2013

Thanks for the replies!

jamesman: I used xnormal and baked a highpoly sculpt to a low poly. I made the low poly first if that matters.

Alec: Ill get that pic of the high/low poly tomorrow. I am not triangulating before baking.

Belkun: What is a cage and how do I use it? (still learning a lot hehe)

and I will definitely mirror the uv's.

Again, thanks so much for the replies.

belkun · Dec 2013

A cage is basically your lowpoly expanded so it covers the highpoly and sets a "limit" for when you're baking the textures.

Are you using xNormal to bake? You can create a cage by launching its 3D Viewer and doing a global extrusion. Alternatively, I do it using Maya, selecting all of the verts on the lowpoly mesh, setting the Move Tool axis to move along the Normals, and just pull everything until it covers the highpoly, then do some individual tweaks and stuff. You can set up the cage by right-clicking your lowpoly mesh on xNormal and selecting Browse external cage file.

I'd really recommend you to read more about normal maps here.

kite212 · Dec 2013

Here is what I would do for this specific model. First you are wasting TONS of UV space. the model should be mirrored so you are only making and unwrapping half of the model, so address this first.

It is simple enough that a cage should not be required in xNormal. First either make it so the blade an hilt are separate, or export them separately. In xNormal go to Tools > Ray Distance Calculator. Click go and let it run 10 sec, and then stop it and copy the results. Once this is done bake your model

Edit: In the end you should really have a UV more like this, remember mostly, items only have a 256x2 limit.... mostly

waffles.c · Jan 2014

Thanks again yall!! I managed to fix most of my problems by making a cage and adjusting some other things. Thanks again!!

Normal Map Problems

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