How to cast shadows on movable objects?

Mac3D · October 23, 2017, 10:45am

Hi everyone! Im developing a VR experience and Im having quite a lot of problems with lighting. I can´t seem to cast shadows on any objects using an emissive material on a mesh that lits the whole scene. The object I want to cast shadows on is a pickable one using the touch controlers on Oculus so I want the object cast shadows once the user grabs it, sounds simple right? No idea how to accomplish this.

I´ve read some people say the mesh emissive needs to be movable in order to accomplish this but doesn´t work either. Using a dynamic light to fake the shadow of the emissive material doesn´t seem to work at all, in fact if you take a look at the screenshot you will get what I mean.

Does anyone have an idea of what I might be doing wrong? How can I cast shadows on movable objects using an emissive material, and why once I drag the emissive mesh material on the scene all other lights that previously worked fine and casted shadows seem to don´t work anymore? Thanks in advance

anonymous_user_731acd47 · October 23, 2017, 12:46pm

Here’s a checklist for emissive lighting:

The object that is emitting light has to be static
In the lightmass settings of the static mesh Use Emissive for Static Lighting has to be checked
In the material Emissive (Dynamic Area Light) has to be checked
In the material Used with Static Lighting has to be checked
Additionaly, check the value of Light Map Resolution on the objects upon which you want to cast shadows

Mac3D · October 23, 2017, 1:27pm

Thank you Neelix32 for helping me out, unfortanetly I forgot to mention I had those same settings already checked. Anyway I tried an empty level following your advice and doesn´t work, static objects seem to cast shadow but any movable objects I pick up with the motion controller doesn´t cast any shadow at all, I dont know what I´m doing wrong or if its actually not possible to cast shadows of movable objects inside UE 4.17… I´m really frustated

anonymous_user_731acd47 · October 23, 2017, 2:33pm

Emissive lights will not cast dynamic shadows because they have to be baked in the lightmass. You can try setting up a stationary light close to the emissive so that the shadows come from the stationary light and not from the emissive.

Mac3D · October 24, 2017, 9:13am

Hi again! That´s what I tried yesterday and it worked, I read somewhere though that emissive materials cast shadows when you crank up the emission really high, but that didn´t work for me. The only problem is that I have light ceilings on a supermarket with an emissive material on it and a point light as movable for each one of them and now the performance on VR dropped down and makes it impossible to even test it, really really low frame rate, shall I reduce the ammount of point lights on the scene? Thank you Neelix32!