best script for bevellling+ normal map question

Ruz

Yeah , trying to do some slightly more techincal stuff. Just thought bevelling edges was the way to go. Any suggestions as to the best script for bevels. Meshtools perhaps?
Also if I buld in my bevels manually, then would I delete them after baking my normal map or is it just not possible to make a right angle look round.
The reason i ask is that i don't really want the pain of building manual bevels if I can get away with a faster method.
Imagine a tv which is basically box, but with round edges.
Ideally I would just have a box( with right angles) as the lowest level, but results have been pretty awful as if you assign a smoothing group of 1 to the whole box, the vertex shading is very poor and messes up the look of the normal map.
Any help would be appreciated:)

Archanex

What software are you using?

osman

Hey im not sure if this is what you mean, but ill go ahead and show this anyways:).

You shouldnt have any vertex shading problems, because it only apears if you try to give a whole box smoothing group 1.And you never have to do that.
If your bevel is so small that your low-poly can be a box, then that means you can have different smoothing groups for the low-poly faces.
But if your bevel is bigger than that, then it means you have to add more polys to your low poly version, and by doing so you will get rid of the shading issues because of the smoothing group(more poly+1 smoothing group = ok).
So i cant imagine a case where you'd have to create a box as the low poly AND have all its faces on smoothing group 1.
My english is poor i know, so ill try to explain with an image:
from left to right: wireframe low poly,vertex shaded low poly,normal mapped low poly, high poly

Anyways, maybe this isnt what youre asking, in that case im sorry:).

NeoShroomish

If you need to have it in 1 smoothing group, you can use the inset tool on all the faces (if you're using max).

Ruz

Right thats cool. the confusion has arisen because I have been doing characters for the last 4 years and have never had to do this stuff.
_Oz,thanks for that diagram, very instructive. The only problem is now that in the case of the simple box, when I subdivide it turns in to virtually a sphere( in max BTW). To get around this I turn on separate by smoothing group and then subdivide a few more times.
Unfortunatley when i render the normal map, the hard edge of the low poly gets burnt in also. So i get a normal map that is producing a round edge on top of a box with hard edges. Any way to avoid this apart from going slightly higher poly with a chamfer box?
The reason i got confused was that it seems to be common practice to assign one smoothing group with characters, because they don't tend to have vertex shading issues as they are reasonably high poly these days.

vahl

the lowpoly should have as few smoothing groups as possible, like characters,the shading "errors" of the lowpoly will get "baked in" if your renderer is good enough (I'm assuming you're using max, so the renderer should be fine), so you may notice artefacts on the normalmap, but they are here to "fix" the shading "errors" of the lowpoly. the important being that the lowpoly must have the same smoothing group setting ingame than when it was baked, usually people tend to try to avoid angles sharper than 89.5° in the smoothing group settings, except if you're using an unique normalmap, in that case, 180° all the way

then things are different if you're using tiling textures or trims, in that case, it may be wiser to smartly use hard edges/bevels combinations on the lowpoly to get the round edges where they need to be but also fix the shading errors that the normal map will not fix (since it's not baked in it)

I also tend to place the bevelled edge of a normalmapped trim even on an hardedged model, it tends to soften it slightly, and if you're using baked lighting, that should soften it even more.
if you're using realtime stencil shadows, bevel is the best way, since hard edges will be superobvious, wether they are nicely/uniquely normalmapped or not.

osman

Dont just subdivide, if you dont want your boxes to turn into spheres you'll need to put some new edges across the corners.
Check this image(this mesh isnt clean at all, was just to show what i mean:).


Oh and it may sometimes be kinda hard to guess where to put edges, in that case you can try dubplicating your model(select reference mode) move it away to the side, throw a turobsmooth on top of the new copy and turn on the subdivision to 2 or 3. This way you can work on your original and see whats happening in real time, no need for switching to subdivision mode(it can be laggy).

Ruz

ok, thats what I wanted to avoid you see, adding more geometry.
In this example I have almost made it work. The smooth edge you see on the left is mapped on to a hard corner. I think it doesn't work on the right because I have separated the uv's along the edge


In your second pic above, would that be your final low res model ie with all the extra edges built in, or would you optimise it again after generating the normal map. I am guessing that if you did optimise it again, it might look wrong.

osman

Can you show how the high poly looks for the right picture of yours?
And about my low poly, i'd create a whole new one,one that matches the high poly and one thats optimized as hell.

Ruz

I have reasons Per , it's called time is money and i don't want to spend extra time building in more geo if I can get away witha faster method:)
_Oz , so your optimized one would still have some bevels on it?
I just just noticed Vahls post about the stencil shadows and yeah now I think about it, even if I managed to fake it using my cheap ass method, it would still look wrong with shadows in game

Joseph Silverman

How much time does it take to add a few edge rings or use the chamfer tool, ruz? 'building in more geo' should take you a lot less time than this thread has, so far.

osman

for the low poly mesh, you'll have to find a balance between matching the high poly's silhouette and still keeping it low poly.

Ruz

Just to clarify,In the case of a simple box

1 you build in all the extra edges/bevels you need so it will subdivide properly.

2 generate the normal maps using the usual method

3 leave the bevels intact on the final in game low res model, not turn it back in to a right angled box?

man, i often get stuck on the simplest things , then go and solve some other complicated problem:)

Suprore, I had to clarify more than just the bevel issue. i need to keep these assets I am doing fairly low poly, so was trying to find a method to accomodate this. Sometime a day spent researching can save you a lot of time in the long run:]
EDIT Cheers for that _Oz,everyone, i am a lot clearer on stuff now.

MoP

They have a point, Ruz :P
Time is money, so don't spend ages trying to figure out a "fast way" if there's already a way which works fine...

Don't bevel or subdivide the box you're baking to, bevel/subdivide/chamfer whatever the highpoly source is. The low-poly shape you're baking to shouldn't need to be edited at all. No chamfers needed.

Ruz

I think you are misunderstanding a bit why I am struggling here, its not so much the techniques for building objects,though i have taken on board the technqies posted here, its the look of the final normal map on a fairly hard edged low poly object and the issues with smoothing groups.
Vahl hit it on the head when he said if you tried to map a smooth edge on to a low poly right angled box, the stencil shadowing would give it away in game.

The stuff about bevelling was just another issue that i was dealing with.
I probably should have explained it better.
Here is a diagram

The one on the left I would use to make my high poly model and the optimised one on the right I would use for the my bake.
All i wanted to know was could I take the optimised one back to a right angle box without messing up the look of the normal map, but it seems not from what has been posted.

Ruz

Yeah I jsut wanted to see how low I could go without it looking crap.
More of an experiment really.
Its kind of sunk in now that its the same as doing characters, the low poly should match as closely as possible to the silhouette of the high, so keeping in those bevels is a good thing anyway.

Thats not a tv BTW, its a suitcase with some robots hiding behind it:/

Anyway I am sorted now, thanks for the help dudes, appreciate it.

Ruz

yeah the last technical stuff I did was 2 years ago , building stadiums for PS2 stuff and not a bevel in sight.
I was just having a go at some tech stuff now I have a bit of spare time.