Static Mesh lighting issues - advice needed!

[D-Rez]

Hi guys,

I'm working on a large-scale project for university and have encountered a bit of a lighting issue with some of my static meshes.

I have a network of roads that have been built out of seperate meshes (think Scalextric race tracks or model railways, same kind of approach used here). Thing is, when building the scene, I get shadows being cast that are creating 'seams' between each section, like this:



A, B, C, D, E etc. are all seperate static meshes, and have been built so they line up properly (no steps or height difference and they all snap to grid).

I've had a look at lighting importance volumes, making seperate lightmaps on each mesh, changing the lighting build quality and i've also had a look at some of the Hourences tutorials but the issues are still there. Any thoughts or tips?

Additionally, I do have a low point light in the corner of the scene (I wanted to make the lighting look more like a sunset and cast long shadows) which is still higher than all the meshes - could this be the root of the problem? Also, I'm still using the January UDK if that's any help.

I'm no expert on lighting a level as you can tell, so any help or pointers will be gratefully received. If anyone has any good UDK lighting tutorials i'll be more than happy to take a look and see if they can help out too.

Thanks in advance,
Rez

[Visceral89]

Have you tried what result you get with a dominant directional light? Points light shouldnt really be used as skylights.

[SethPDA]

If you tryed everything,this can be a graphic card problem.
I've had these kind of lighting before in some games when I had a much worse graphics card.Not sure if that's the prob cuz you don't mention the PC specs,but it could be this also.
If it isn't,then try not to collide meshes,that can screw up shadows sometimes,at least for me,make everything EXACT,don't put 1 mesh's one part in the inside of the other so they collide and lightmass calculates the light wrong.This happens to occure for me sometimes,but not on all meshes,but only on my custom ones,don't know why :-/
(Don't blame me if I'm wrong,I just wanted to help)

[Xendance]

As previously said, use dominant directional lights for sunlight, they can be rotated to give that morning sun look :P

[5hfifty]

The edges of the meshes look like they have smoothing applied.. try setting the open edges to hard edge in your modeling program and exporting with smoothing groups.

That's what it looks like to me at least.

It looks especially pronounced because the objects are lowpoly, pretty much the whole road is treated as "smooth" by the lighting as it's trying to smooth out the hard open edges.

[D-Rez]

I've got a GeForce 9500 in this machine - i'll try the map on another machine when I get a chance and see if it makes a difference.

I've also had a go at using a directional light (thanks for that - it's much better lighting wise but unfortunately still hasn't resolved my shading issues). I did find a nifty lightmass tutorial while working it out though, if anyone else needs an intro/explaination of certain lightmass options: http://www.chrisalbeluhn.com/UDK_Lig..._Tutorial.html

I did also wonder if it was an issue with normals, but I've gone the opposite way and used 'average normals' in Maya - i'll try the opposite and see if that helps. I was kinda hoping it was a problem like this with the meshes themselves actually, because i'm much more familiar with Maya than the UDK. I'll keep trying

Thanks for the advice so far guys, I appreciate it! If anyone else has some thoughts, please feel free to chip in.

-Rez

[taz1004]

Do you have separate UV channel for shadows? And how are the UV's laid out? As for average normals, don't use it. Use either soften edge or harden edge. I found that using normal angles in Maya doesn't translates to UDK.

[darthviper107]

Make sure your lightmap resolution for your static meshes is high enough, it looks like it's probably very low

[Visceral89]

The edges of the meshes look like they have smoothing applied.. try setting the open edges to hard edge in your modeling program and exporting with smoothing groups.

That's what it looks like to me at least.

It looks especially pronounced because the objects are lowpoly, pretty much the whole road is treated as "smooth" by the lighting as it's trying to smooth out the hard open edges.

I would go with this. Just delete the endcaps and fix your smoothing groups inside max or whatever you are using

[Neji]

It's not my thread but I've just experienced the same thing. Deleting the end caps and fixing the smoothing groups works perfectly. So I'll just say thanks to the above replies suggesting this

[spin]

Indeed, smoothing groups for sure, imo. If you use max, take a couple of those meshes, select all polys and hit autosmooth with a value of 1 for quick and dirty smoothing fix, don't even need to delete the caps. Not sure on maya, since I don't use it, but it's going to have the same function.

For simple meshes with lots of 90 degree bends I find this to be the fastest way to ensure properly setup smoothing groups.

Bear in mind if you don't everything is set to smoothing group 0, which is what it looks like we are seeing here.

[Visceral89]

Indeed, smoothing groups for sure, imo. If you use max, take a couple of those meshes, select all polys and hit autosmooth with a value of 1 for quick and dirty smoothing fix, don't even need to delete the caps. Not sure on maya, since I don't use it, but it's going to have the same function.

For simple meshes with lots of 90 degree bends I find this to be the fastest way to ensure properly setup smoothing groups.

Bear in mind if you don't everything is set to smoothing group 0, which is what it looks like we are seeing here.

Yup this works, beacuse the default smoothing angle cuts smoothing groups to a 45 degree angle. But just to make sure, check the angle so that it really is 45degrees.

[D-Rez]

Thanks for all the feedback guys - apologies for not replying sooner, My internet connection has been pretty lousy recently.

Deleting the caps seems to have done the trick in my case - also my normal maps were a bit off, which probably just drew attention to seams. I just got rid of them and everything looks much better now.

Cheers!
-Rez

[Visceral89]

Any chance of seeing the finished product?

[heroicsatsuma]

What do you mean by fixing the smooth groups - I use 3ds max and am having this issue on import into UDK

I have cleared all smooth groups before export but am still experiencing this problem - I thought as my model is all hard edges i wouldn't need smoothing groups to be specified - Is this incorrect?

Thanks