Been working with gaussian splats for a while and the thing that always killed it for me is that you cant really do much with it in Blender. Looks incredible in a web viewer, you import it, and then it just sits there ignoring every light in your scene. Seeing Houdini implement self-shadowing got me thinking.

So I built an addon. Splats come in as normal scene objects. Your lights affect them, and they self-shadow, driven by each gaussian's opacity rather than a proxy cage, so wispy parts stay soft instead of turning into a solid blob. Works in EEVEE and Cycles although Cycles isn't recommended since the transparency light paths needed for this method to work tanks performance. I believe Blender foundation is working on this exact problem right now so hopefully we see some improvements in the near future.

The free (LITE) version is the whole viewer and relighter, not a demo. You get the full shading, the relighting and self shadowing, and export back out to standard .ply. If what you want  
is to get a capture into Blender and light it properly, that is the free one and you're done.

Other things I ended up adding that I believe will help professionals implement this into their workflow. (Pro Version)

Build a proxy mesh off the splat and bind to it, then the splats ride the surface through armatures, lattices, shape keys, cloth, softbody. This should also allow for sims such as water and smoke sims to actually be affected by your splats. Weight paint a mask and transfer PBR onto the splats, so you can paint emission onto a captured car and the headlights actually glow. Bake your scene lighting int the splat so the relit look survives export back out to .ply and still looks right in SuperSplat. Crop, shave floaters, merge, decimate. Pull in the capture cameras from a COLMAP or nerfstudio solve. Play 4D captures back on the timeline. And it'll train a splat from any video where the camera moves, locally on your own GPU.

You can find the addon here on: [Superhive (formerly Blender Market)](https://superhivemarket.com/products/splatlight)  
You can also find it on gumroad

Gaussian splat self-shadowing natively in Blender