Terrain shadow problem

andy2626

Hey there guys my name is Andy and this is an environment I have been working on an for some time as part of my final year project at uni; and believe it or not this is the first time I have ever used UDK. . I have had loads of set backs and am still experiencing some but I'm almost done now.

he main problem I am experiencing at the moment is strange striped shadows on my terrain. Had a little look round the other forum threads and I think it may be something to do with shadowdepthbias. but still haven't found anything thats helped. I have a dominant directional light in the scene and both static and dynamic objects in it too. Any help would be much appreciated as I have done a video fly through but the shadows are making it look crap!



Here's a link to the album on imgur

radiancef0rge

Yeah thats some wack ass shadow acne. See if this fixes your problem - if not youve got as few other options check out "shadow acne terrain udk" or something on here

XilenceX

Yeah its pretty much either changing shadow depth bias or making your terrain out of static meshes that have bUsePrecomputedShadows turned off. I am not aware of any other solution and both obviously have significant tradeoffs.

mAlkAv!An

I gotta say this does not look like typical shadow acne artifacts, more like some issues with the landscape material, a wrong projected texture for instance. Can you post a screen with lighting only?
Also if there are static objects and no moving light you might be better off to bake the lighting for those object and the landscape/terrain.

andy2626

Well I had a look at that forum thread and while it is useful I cannot find the shadowdepthbias in the baseengine.ini any idea where abouts it'll be? also here is a screenshot of the lighting only. I have changed a few setting on my dominant directional which has improved shadow quality however I'm still getting the 'shadow acne'. Its starting to piss me off now!

Xendance

If you don't need terrain to cast shadows, turn off self shadows. That fixes it.

andy2626

Ahhh I think I have solved it. I changed the angle of the sun slightly which made a small difference but I found and changed the shadowdepthbias from 0.012 - 0.05. Found this in the UDKsytemsettings.ini.

mAlkAv!An

That's fine. However such large bias values will introduce lots of 'petter panning' (= floating shadows) in return. Might look bad in some places like all the tree trunks.

Alternatively you can switch to DX11. I know it has its own issues and drawbacks, but shadow acne is only a minor here due to a higher depth buffer precision (which is btw. the main reason for all the nasty shadow acne in DX9).

andy2626

How do you switch to DX 11?

mAlkAv!An

http://udn.epicgames.com/Three/DirectX11Rendering.html

andy2626

thanks!