normal map hard edges

lloyd

Hello, I'm trying to make a normal map for a low poly object from a highpoly object.


however i am getting big hard edges on my normal map. iv put the side of the object in 1 smoothing group, i just don't know why this is happening. it doesnt seem to happen to other bits of the model





there was some problems on one side but i sorted them by changing the smoothing groups of the inset section. heres what it looked like

pior

Old rules still apply ... this lowpoly would never work properly no matter what. (well it might work on a movie render with projected textures but thats about it). Make horizontal cuts, avoid those crazy sharp triangles.

Once there, you can start messing around with advanced normalmap techniques : hard edges on the low with corresponding split apart UVs. But thats for later - fix the lowpoly meshing first!

If the normals are baked in max RTT and previewed in max viewport, it ll look wrong too (see the big thread in technical talk)

Good luck!

lloyd

Thanks for the reply. i was trying to keep the polycount low so i didn't think long tris like this would be a problem, I'll go back in and add some more geometry.

As for previewing it in the viewport would you suggest using Xoliul's 3DS Max Viewport Shader to view my lowpoly models?

[HP]

yes, xoliul's a nice shader, use it.

You're low poly is really messy. Avoid having too many edges ending up on the same vertex, and try to have as much linear and parallel loops as possible, that way you wont get wonky shadding from the smoothing groups.

or... if you're lazy, follow the tutorial by heart, and use polycruncher!

lloyd

lol HP ...shut up!

i'm transitioning from xsi to 3ds. so i took it into xsi and used "reduce polygon" as people were saying i should stay away from polycruncher.

i always thought low poly work was about saving polys. so thats why alot of the lines end up on the same point/vert i guess i have to not be so tight!



on another note. iv got to stop going to your website and looking at that leather chair! when can i get a copy of it!? high and low.

also could i see a wireframe of this
http://www.helderpinto.com/ssp_director/albums/album-6/lg/render2.jpg ?

Thanks

Eric Chadwick

I think you should be using an object-space normal map for that asset. That way only the silhouette matters, not the interior triangles. Well, except you should avoid long thin tris.

[HP]

ah ah! :P Well, (If I'm not mistaken) the reduce polygon tool from XSI, creates similar results to the "MultiRes" modifier on max.

PolygonCruncher is ok for this kind of meshes, if you edit the result afterwards that is, because the result is almost always pretty messy and you end up with more geometry than you'd really need.

Oh man, that pillar! :X I did it while following the pillar tutorial, was a noob back then. hell, I still am.

fantasymaster

just moove the uv shells slightly away from each other where you have a hard edge.

Guriamo

I second that, a small gap between the Uv shells and everything will be fine ...

lloyd

So for each side of the pillar i need to set a smoothing group. i also then need to set one for other sections such as the inset pieces.

i then need to seperate the uvs of the diffrent smoothing groups. as at the moment i have the whole pillar sides attatched to one big lump.

i can't just detatch them but i also need to move them away from each other abit...silly uv

will the padding amount help with how far i need to move uvs? also how do i change the normal to come out as an object space normal? is it somthing to do with the drop down which says bump?

Eric Chadwick

If you can use an object space map, then the smoothing groups don't matter (though it's better to set the whole model to one SG, since that reduces the number of in-game vertices). In Max's RTT, open the Projection Options dialog to set it to object space.

This asset would be best with object space, since it's easier to get a seamless result, you don't need to re-use the map on other assets (have to use tangent space if so), and ultimately it's better for performance (though you can't compress an OS map like you can a TS map).

osman

An OS map would work really well, but this asset is very do-able with a TS map, so I'd suggest trying to do it with a TS anyways, for practise.
And perhaps you could try Fozi's normal map converter on this asset, see what kind of results it yeilds .

3DRyan

This may be noob talk, but couldn't you just almost make the pillar a simple cube? I mean, in terms of silhouette, it would work, right?

mLichy

All of those issues or most all are from improper edge cuts/placement on the lowpoly. It looks like you applied 1 smoothing group to this?

Make sure to have edgeloops/cuts close to the edges when doing 1 smoothing group to compensate for the wrapping it has to do for the normals. Also, remove anything that doesn't affect the silhouette in a pretty obvious way. The normals will usually work well enough.

Look over your low before baking, and make sure there aren't any harsh or noticeable dark edges or patches. Those will show up in your final map, so don't ignore them.

Also, after you bake the map, if you're using max, apply the normal map to the object with the normal bump map in the bump map slot and turn on DX preview (Hold down on checkered pattern box in mat editor and click on the blue one). Then once it's showing up, apply an edit normals modifier, and turn it on and off to notice what it fixes.

It takes your lowpoly normals and matches them to the HP baked normals to fix up some weirdness and whatnot. Then just collapse the stack if it looks good.

Hope that helps.

Eric Chadwick

3DRyan wrote: »

This may be noob talk, but couldn't you just almost make the pillar a simple cube? I mean, in terms of silhouette, it would work, right?

Only if you were making it for the original Doom. Try it out yourself, it'll become pretty obvious pretty quick.

lloyd

I changed the normal map space to local XYZ and everything seems to have come out amazing even with the "dodgy" triangles.

My question now is, if i can save alot of triangles by making objects in this way and then just make an local space normal map, surely that's better than having something with a higher poly count and a tangent space normal map?

optimisation?


Also i'v tried googleing stuff about the different types of normal but i can't see any pros / cons for tangent vs local? However most normal maps i see for game assets are tangent. why is this?


Thanks for the help!

Vrav

Absolutely love object space normals for this reason. NO idea why tangent space is ever used for a static prop like this.
(besides the ability to blend in detail via CB / nvidia plugin / whatever)

EarthQuake

Mirroring, ease of adding extra bump detail, and compression(there are a few TS specific compression formats, OS compresses really poorly) are a few reasons

Eric Chadwick

Did a little revising to make this easier to read.
http://wiki.polycount.net/Normal_Map#TangentSpaceVsObjectSpace

Vrav

True. I still think object space looks great though, and it's really easy to bake (saving time). I have personally stopped using them in my portfolio for the sake of practicing tangent space, but... visually, on uniquely detailed props, object space wins.

MRico

I have a question...I read the whole "Why you should NOT use 3ds Max..." that MoP started...and towards the end fozi made that software to convert OS to TS...now, seeing that lloyd baked it as OS and it came out just fine without those weird triangle shading...if he converted his OS to a TS would that TS normal map override the triangle shading issue of the low poly?

Eric Chadwick

Maybe. But only if he uses a Standard material with a Normal Bump map, and enables "Show Hardware Map in Viewport". The in-game result is what really matters, he should get it into Unreal Ed or Marmoset or CryEngine or somesuch.

lloyd

hello! all this is really helping me. iv moved onto trying to make a gun. im at the lowpoly stage.

I'm trying to make this work with TS. so as far as TS and my triangle problem. is this type of tri layout going to cause problems?

EDIT:

What about this? a step to far?