Lighting problem: skin glow at the bottom

RobertDy

Hi,

I render with 3Delight and use AOA's Advanced Light Bundle. It's worked really great for me but I have an issue recently and this might be universal for all lights probably.

As you can see from the attachment, a person is lying on the floor and an arm is shown. You can see that there is some sharp glow at the bottom of the arm while the rest is covered in a shadow. The glow looks really weird of course so how do I get rid of it?

Thanks!

AndyS

Yep!

That's a knwon feature of UE2. It is related to the shadow distance.
Install a second plane with its distance between "Shadow Bias" and "Maximum Trace Distance".

RobertDy

AndyS said:

Yep!

That's a knwon feature of UE2. It is related to the shadow distance.
Install a second plane with its distance between "Shadow Bias" and "Maximum Trace Distance".

Thanks and this is new information to me. When you mention plane is it a plane primitive? Sorry I'm very new to this. How do I determine the distance between shadow bias and maximum trace distance and where can I find these two parameters?

AndyS

In common, simply doublicate the surface, for which this effect has to be eliminated.
For "buildings" / "rooms" I most times created a close "shield" around it.
Otherwise you'll get these artefacts at all corners of the room, at all surfaces touching a different one, etc.

The values I named are parameters of the UE2 setting.

RobertDy

AndyS said:

In common, simply doublicate the surface, for which this effect has to be eliminated.
For "buildings" / "rooms" I most times created a close "shield" around it.
Otherwise you'll get these artefacts at all corners of the room, at all surfaces touching a different one, etc.

The values I named are parameters of the UE2 setting.

If I 'shield' the surface like in the attachment then my distant lights would be blocked and the lighting effects be completely changed. Also when you mean 'shield' do you mean shield at the top? because in my environment it;'s a wall enclosure but there is no shield at the top, so light can pass through from the  top but not from the sides which are blocked by walls.

AndyS

Perhaps I described it not quite clear.
But the example demonstrates it:

Every surface needs a second (ideal: same geometry) surface in a little distance (outside / below / above) to avaoid the "Shadow Bias"-Bug. It is the same reason why caharcter's skin "glows" in the dark.

The Shield shouldn't block your light sources. It is only shielding your existing surfaces against this UE2 artefact.

In the picture you see, that the shields are "copies" of the corresponding walls / floor / ceiling and positioned in a small distance. No additional planes.

I don't know how to desribe it in a better way ...