Lightbake on Destructible Meshes

I have destructible meshes in my level that are not receiving lightmass info.

There is an option that I have been using for most of my movable options called “light as if static”. If I try to check this box, it will not let me toggle the switch on. Are destructible meshes not movable objects?

I understand that destructible meshes could potentially be messy for lightmap UVs on meshes. Would the best route be to use a static mesh until it receives a hit? Then swap out that mesh for the destructible?

Thank you in advance! Cheers!

Hi,

Destructible Meshes are closer to a skeletal mesh in the way they are setup. Once the destructible is fractured you get a root bone with each chunk being its own bone. So with this in mind, DMs cannot have lightmaps or use precomputed lighting.

To light these with statically (precomputed) lit environments they use the indirect lighting cache to blend them into their enviornment. Swapping the mesh out is what I’ve seen a lot of people do, but if you’re using the “light as if static” for movable objects keep in mind that the static mesh will cast a static shadow as well and if you swap it out with the DM that shadow is baked in and will remain.

Yes!! Thank you so much ! I really do appreciate this answer. It is exactly what I needed.

I started using the Lightmass Character Indirect Detail Volume where it is really needed.

Also in the world settings I lowered the Volume Light Sample Placement Scale to 0.1.

Some of the objects in the scene are basic household items that the player can break. For example, tables, chairs, etc. Is there anyway to make those objects feel grounded? A lack of shadow detail is all I’m missing at this point. Any thoughts?

Thank you so much, !!

Oh by the way, . I left out some details about the project. This is a VR title and we are staying away from dynamic lighting and shadows. We are also using the forward renderer so contact shadows are not an option. Cheers!

Some of the objects in the scene are basic household items that the player can break. For example, tables, chairs, etc. Is there anyway to make those objects feel grounded? A lack of shadow detail is all I’m missing at this point. Any thoughts?

Not currently, at least not dynamically. In 4.15 we’ll have a new feature for dynamic indirect shadowing for static meshes using Distance Fields and with something like that you could easily switch out the dynamic static mesh with the DM when it’s hit so that you get the grounded feeling. Since you mention you’re using VR that would be costly to have, though!

Alternatively, you could always fake the effect. In the VR Demo we released for Epic Showdown (the city street demo), dynamic shadows are expensive and since this environment is only statically lit we had to have shadowing under the dynamic objects. The characters use this along with the Police car. These are all set in the blueprint and using a material with depth applied to a mesh. You can download that example and see how it was setup for the police car so that it had a semi-accurate shadow cast for it in these indirect-lit areas. That’s probably the best example to get you started for something like this

Great! Thank you so much, . This information is extremely helpful. I will definitely take a closer look at that scene. Cheers! :slight_smile: