Aliasing and blotchy shadows. How to clean up?

anonymous_user_6096f04f · September 2, 2015, 1:27pm

After a month of not having the program I have dived back into learning it. In this test scene how to I clean up the blotchiness around the cylinder and the aliased shadows?
It’s a Sketchup model imported into UE4.

Thanks!

Enter_Reality · September 2, 2015, 1:43pm

The blotchy shadows are due to the floor resolution…boost the resolution a bit and you won’t see those.

About the “aliasing” that is not an aliasing problem but I think that the colums is not in contact with the floor and the column itself is not too “round”, so I suggest you to snap all the vertices of the lower face of the column on the floor and increase the edges of the circle so that is looks more round

anonymous_user_6096f04f · September 2, 2015, 2:09pm

Thanks for the reply. The circle/column is just from the included content as a test for lighting and shadow. The aliasing I am talking about is the shadows cast on the floor from the window mullions - they should have soft smooth edges. What causes that?

Also, I see several places to increase the lightmap resolution. Which is the correct method?

Rob_Wu · September 2, 2015, 2:27pm

Hi,

The artifact are from a lowres lightmap, as Nicolas3D said.

Increasing the lightmap resolution would be on a per object basis. Often the default of 64 would be enough. If you get artifacts, uncheck the box and start multiplying the resolution: 64-128-256 etc. untill the edges are smooth.
I’m a newcomer too, and found out only walls, ceiling etc, need large(r) maps. It’s also best for large surfaces to split it up inot several pieces, to keep the UV/lightmap ratio into check.

rob

anonymous_user_6096f04f · September 2, 2015, 2:44pm

Thanks Rob. I see under the “Build” drop down a place to change the lightmap resolution, I also see an override lightmap resolution in the details panel and there is a lightmap resolution if you highlight the object in the details panel right click and select “edit” which opens a panel with a lightmap resolution setting. So, I assume the override is global meaning it effects all lightmaps?

anonymous_user_afa92833 · December 18, 2017, 1:36pm

Check out this awesome lighting guide I found to solve this problem: #Lighting_Quality_comparison.2C_or_Production_.3E_Preview

The shadow aliasing has a lot to do with your Engine Scalability Settings under your level settings tab… try “Cinematic/Epic.” There is also a specific section on splotchy shadows as well, which has a lot to do with lightmass settings and map.