Normal mapping hard edges problem

boyluya

Hello guys. I starting to learn normal mapping for hard surfaces, and decided to start with a simple cube. And yep I'm already having a problem. There's some weird seams all over the edges, and I can't firgue what causes this.

All the cube's edges are hard edges(different smoothing group) with their uv's split. I used xnormal for baking (and its sbm exporter) and Xoliul's shader for display.

the problem


uv's


normal map

Ballo

The problem is the hard edges in the low mesh.

boyluya

So there's no way I can bake a normal map from hard edges?

Ged

boyluya wrote: »

So there's no way I can bake a normal map from hard edges?

why would you want a normal map if its just a hard edged object? maybe just dont use a normal map? I had to do this recently on a scene with a very square light fitting

boyluya

Ged: I'm baking a normal map from a high poly cube into a low poly cube(with hard edge).

Baj Singh

http://boards.polycount.net/showthread.php?t=68173

Make sure you read through the entire thread if you have the time, its a very good read and should help you out a lot.

serialkiler

i can see the problem but lack the words to explain it.
but ill try xD

put the normals back to normal, in your normals u made it soft edges (round) but u want them hard edges.

im not getting what u trying to do

sama.van

Pure hard edge doesn't really exist when come hi poly work.... it's always done with a very tiny Bevel getting a better render.

90 degre angle are not so friendly with normal map... sometimes work but...

You can use hard edges on Crystal, but on another object if you add a very very tiny bevel it will make your object more friendly when baking the hipoly on the low.


Also you can try to add more edges on your low poly model you will use for the bake setp.
Do not use directly your low poly model in game!

===========================
Very last thing : Think mip-mapping...

Your problem could be only because you left only one or 2 pixels on your uvs border.
Then mipmapping is creating shitty effect.
They call that paddings is 3dsmax?? I think default is 2....
Make more space between your uvs and switch to padding = 20px for the test

===========================

Try to 2 create 2 line of 3 square with you uvs

Teclis

Hey, i think the problem is the baking of xnormal. Afaik it uses raycast by default, try to export a cage or bake it in max with cage.

boyluya

Thanks guys. Yep the problem is i forgot to check the "use cage" setting in xnormal and the alos edge padding is too low.

pior

Yeah, you're actually doing it just right (split/hard edges on low, split UVs, and highpoly model looking, well, just the way you want it.) Most of the answers above missed the point hehe. Yup simply make your UVs islands more spread apart, and make sure you have a big enough 'bleed' border (5 pix or so)

It's all explained, amongst other things, in the thread linked by Baj.

Good luck!

[Deleted User]

You can also chamfer all the edges on the low, set it all to one smoothing group, apply an edit normals modifier, check "face" in the select by section, then select a side of the cube, average the normals, repeat for all the other sides, leave the bevels alone, and it'll look awesome without a normal map. (Assuming that whatever you're going to put it in supports the modified normals.)

Bal

Teclis wrote: »

Hey, i think the problem is the baking of xnormal. Afaik it uses raycast by default, try to export a cage or bake it in max with cage.

What he said, you're doing it right otherwise.
If you want it to work right in xNormal with no cage, you'd have to have the edges of your low poly cube flush against the surface of the high poly one (hard to do in most cases).

boyluya

Thanks again guys, I've already figured out the problem and fixed it. This is just an experiment so I can understand the basics of normal mapping hard surfaces. ^^

Ballo

How do you fix it?

achmedthesnake

magic.....

Ballo

hahaha...that will be!:)

boyluya

I fixed it just like pior said. Split the uv's (or break) of those hard edges, increasing the edge padding and used a cage. ^^