Lighting build taking over 12 hours

I have been building the lighting on an archviz project with the following settings, but it is taking over 12 hours to build.

Lightmass importance Volume in use
Lightmass Portals in all openings
Static Lighting 0.35

I have used the lightmass statistics to go through all meshes and reduces resolution where it’s not needed to be 512 or 1024 etc.

Machine is NVIDI GTX 1050 CPU AMD FXtm 6300 six core processor

Any suggestions on improving build times?

I don’t think one can be sure on what is “going on” here, but looking at your triangle count, you have more than 15 million triangles for lightmass to bounce light around, this time shouldn’t come as a surprise. It is not a matter of a machine configuration, it is just the number of triangles you want your computer to process.

Bear in mind that lightmass calculates how light bounces through the scene, this means each bounce of light will have to be tested against a reasonable number of triangles. How dense is your scene? If everything is packed in the same place reducing the quality of your meshes won’t do much.

Of course, I am just guessing how your meshes are layered out, but try to spread the meshes a little bit, delete some of them in order to have more space in between, this can give the collision acceleration data structures more space to work on reducing the number of triangles each bounce of light needs to be tested against.

thanks for your assistance - i have tried your suggestions and they have helped. I have realised my machine is below par as the CPU is AMD 6300 6 core processor - I will be upgrading to i7 which will hopefully improve performance too.