Is it possible to display Shadow on transparent Plane？

cmwlssy · February 20, 2023, 4:06pm

Hello, I’m using UE 4.27 to make a demo for my paper about Illumination Estimation and Image Harmonization

I use my own HDRI map in Skylight, and use SceneCapture2D to show the 3D model on UI.
But I need a plane to show the shadow, and the plane has to be totally transparent.

Here are my project, the background scene is just a picture.

So if anyone know how to display the shadow on a transparent plane?
Or maybe there are some other ways to achieve this effect？

Thanks a lot!

Astrotronic · February 21, 2023, 1:14am

Hi Cmwlssy, Welcome to the Forums.

An optimization trick to make something feel ‘grounded’ with a shadow but saving the cost of computing shadows is using a ‘blob shadow’.

This would be on a much smaller plane mesh directly under your chair.

Hope that helps!

cmwlssy · February 21, 2023, 2:32am

Thanks a lot! I’ll try this method first

AyanMiru · February 21, 2023, 7:20am

Composure plugin allows you to create shadow catching transparent geometry, and composite shadows onto frame. Implementation can be found in Composure Framework project from the Samples tab.

It’s been awhile and I don’t remember specifics, but it’s a direction I would recommend you to check out if you need calculated shadows.

cmwlssy · February 23, 2023, 10:13am

Thanks a lot!