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So I am trying to get out a shadow pass for compositing and it works except for these weird lines that show up across the entire plane. Any ideas what could be causing this?

I'm glad im not the only person with this issue and was planning on posting about it.

But yeah, I have the same problem.

In stand alone if you have ANY light source plugged in except your HDRI, it will cause weird lines.

I dont know if that is what you are seeing but if you have any light sources, try unplugging them.

Also, if you have coherent on it will look like that for a while.

Yeah I think I did track the problem to having light sources other than my HDRI.

But that's a serious issue because it essentially makes the shadow pass useless for 95% of the things I need it for, like comping onto plates. Any word about a possible fix?

dh921911 wrote:Yeah I think I did track the problem to having light sources other than my HDRI.

But that's a serious issue because it essentially makes the shadow pass useless for 95% of the things I need it for, like comping onto plates. Any word about a possible fix?

What's lightingt source? Arealight/emissive geometry? If so have you tried to make opacity zero?

aoktar wrote:

dh921911 wrote:Yeah I think I did track the problem to having light sources other than my HDRI.

But that's a serious issue because it essentially makes the shadow pass useless for 95% of the things I need it for, like comping onto plates. Any word about a possible fix?

What's lightingt source? Arealight/emissive geometry? If so have you tried to make opacity zero?

The light source for me is emission geometry. I haven't tried messing with the opacity, but I will give it a try when I get the chance!

I finally had some time to revisit this issue, and it is definitely being caused by emmisive light sources. Changing the opacity of the material has no affect, other than making the material invisible. Lowering the power down to .00001 has no affect either. Switching off "Cast Illumination" or unchecking emission is the only way to make this go away.

One theory:

It looks like the shadow render pass is catching any potential shadows with equal intensity, nomatter how intense their light source is. For example, when I have an HDRI lighting my scene, along with an area light, the shadow pass shows two equally strong shadows, even though I the HDRI has a sunlight as it's main light source, and the area light is set to 1 power.

BUT then, when I re-enable those problematic emissive materials, the weird lines and unwanted affects return, AND the shadows from the HDRI and Area light return to their proper intensity levels.

So i'm pretty stumped here.

Hi dh921911,
what happen if you export the scene to Standalone?
Do you have the same behavior?
ciao beppe

bepeg4d wrote:Hi dh921911,
what happen if you export the scene to Standalone?
Do you have the same behavior?
ciao beppe

I am away from the office for the rest of the week, but I will check up on this as soon as I return.

Thanks!

Dan

I am having this issue and also tracked it down to 'Cast illumination' inside the Texture Emission node. Disabling fixes the problem with the shadow pass. I can confirm the problem with and without an HDRI light source, or any other light source for that matter. The scene above does not have ANY other light source.

Project file attached.