Problem with shadow due to daylight

Hi, I’m currently working on a project for which I want to simulate dappled lighting patterns with UE5. First, I’m testing UE5 to see whether this tool is suitable to model such patterns and especially the shadows casted by the dayllight. To do this, I want to recreate my set-up in UE5 to see whether I get similar results. Currently, I do not get these. In my set up, as can be seen in the picture, I have two plates, a small brown one and one bigger white plate behind that. The aim is to do measurements on the shadow of the brown plate that is casted onto the white plate behind it. However, currently, there is only a shadow casted on the roof surface, which is the shadow of the white plate. I wonder why I do not see a shadow of the small brown plate casted on the white plate? Can someone help me with this problem?

For the daylight I use the sun position calculator and the settings for Eindhoven, the Netherlands.

Dappled lighting patterns, could you elaborate on what you mean by that?

Unreal engine’s shadowing pipeline is pretty robust, but quality really depends on your shadowing method. If you want maximum and physically correct shadows, use ray-traced shadows or the path-tracer. Virtual shadow maps, traditional shadow maps, and distance field shadows all have concessions that will make them not physically accurate.

And if you are using RT shadows, download the UE5.2 preview. Epic has updated RT shadow behavior to more closely match the path tracer, meaning better physical accuracy.

I think you may just have them positioned incorrectly for the shadows to work…

( I just positioned the light manually, although I’m in Utrecht :smiley: )

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Hi there @Meijke_B, hope you’re well!

This topic has been moved from International to Rendering.

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Thanks and happy developing!

Thanks for your response. Did you use the sun position calculator? Or did you add a sun manually? If you did the latter, how did you determine the exact position of the sun at a certain time, day and location?

The latter, but I didn’t determine anything, I just moved the meshes around, so the shadow was in the right place.

I think that’s all that’s going on with your original pic, you just need the meshes positioned?

So what did you add as a sun in your case? So I cannot create a correct shadow using the sun position calculator? Because I would like to have the shadows realistic and matching the time and location if possible

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If you’re going to use the sun position calculator, everything is preset. The shadows will be correct for the sun position.

The only option you have after that is to reposition objects.

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Thank you for the response, where can I download the UE5.2 preview?

UE5.2 is out of preview and can be downloaded with the launcher.

Is it just the new version of Unreal Engine that I have to download?

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You mentioned that you used something else than the sun position calculator. I’m trying that now, so I added a skylight. But now the colours all appear to be white and there is no shadow at all. Did you add a skylight as light or something else?

Just use a default level

image

When I do that, it automatically opens the sun position calculater connected to the sunsky. Is that the default setting or do you use another one?

Ok, that’s fine. When you have the sunsky in the level, you need to remove the directional light and the skylight, as the sunsky BP already has them.

I set a level up for Utrecht

image

I think I see your problem. The plane doesn’t cast a shadow one way around. Better to use a cube

I used those same settings for Eindhoven, but my results look completely different. I was wondering if you would maybe want to share your model with me, such that I can see what it does with the shadow if I place my geometry in it. It would really help me.

My model? Not quite sure what you mean. The cube and plane are just standard editor meshes.

I can give you a copy of the project, if you like. But that would be this evening…

Yes, if you could send me a copy, that would be great. This evening is fine. :slight_smile:

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I am running 5.2, that ok?

Here’s a link to the project