So i was making this Ikea Bookshelf to sell on the marketplaces, and im just starting the renders after completing the materials, when i tried out the caustics and it actually worked well and did not decimate my render times.
The wood uses SSS and AO and the Glass is basic architectural glass using the light paths node to control the mix between transparent and the beckman glass shader.
The lighting is a 4K hdr (carpentry shop from hdri haven).
The rendering is set to use .033 noise threshold / 1024 spp / OIDN denoiser.
Light bounces are set to 16 max with transmission at 15 and diffuse at 4.
The first image is with no caustics turned on 1 min 51 sec render times. The inside of the bookcase looks dark, especially as there is extra AO going on inside on the wood.
The seconds image i used shadow caustics on just the right hand side as a test.
I enabled this by telling the HDRI to be a caustics caster. The glass panels to be caustics casing, and the wood to be caustics receiving.
The caustics render took 2 min 9 secs.
Actually the final image with caustics on both sides took 1min 55 secs so really no difference to render times as i guess its all down to noise thresholds and the denoiser optimizing the render.
Further tests.
AO increased to 16 samples up from 4. Increases render times to 2 min 28 secs.
AO 16 spp 8K HDRI and slightly increased the strength of the HDRI. Increases render time to 3 mins 9 secs.
Gives more detailed caustics, but at the cost of render time.
