Slow scene - Optimisation Help

[PepperyTakumi]

Hi,

I am rendering a complex scene and it is taking so long to render (even on farms) that it is eating into my budget for the project.

The problem is that it is made of thousands of glossy refractive tubes. Which is obviously slowing down the scene considerably. I am also going to ask around on 3ds Max forums for help in optimising the geometry but the majority of the slow down is the material itself. (It renders fine as clay).

I have created a material with no glossy refraction's and set to (thin) for tubes not directly visible.

I am just unsure how to simulate the look with a simpler material. The tubes need to catch the light and disperse it, I have also added self illumination to the ends of the tubes. But from my testing the slow down is obliviously mainly from the refraction. 

Any ideas? Or is this just going to be one of those projects haha!

[romullus]

Yeah, this surely looks like tough nut to render :] Maybe try to utilise rayswitch material with simplified material for GI?

[PepperyTakumi]

I know... tell me about it!

Ok I will have a look at that. So what sort of material for the GI, just a clay material or will it need to be refractive or opacitated?

Thanks for you suggestion!

[romullus]

Ideally it would have no opacity nor refraction, but you have to try and see how it will look in your scene. In case you'll find that it needs opacity, i would suggest to use refraction with thin mode turned on - this should be the least expensive mode.

Additionally you can try to also optimize render settings by lowering max sampling intensity and maybe even max ray depth in performance tab. Just don't go too crazy low with these parameters, as you may find that render quality will degrade too much.

[PepperyTakumi]

Ok thanks, I am playing with it now.

I have already lowered max depth to 20. Didn't notice to much difference in speed. I could try 15.

I will try a lower max sampling intensity also, never played with this value before any recommendations? (testing the scene is very time consuming)

[PepperyTakumi]

Well I a managed to reduce the time of the secondary Gi a bit by using a ray switch override. Had to use a material with refraction and thin setting, as a normal clay material gave very strong shadows.

Didnt notice any difference changing the max sampling intensity (i only tried 10 mind you)

A slight improvement so thank you. In the end I think I am just gonna have to bite the bullet on this one. Will just render slightly smaller and enlarge in photoshop with a sharpen.... not the best but what can you do!

Thanks!

[romullus]

Didnt notice any difference changing the max sampling intensity (i only tried 10 mind you)

10 is about right. You don't want to go much lower than that, because it will negatively affect GI quality. By lowering MSI, you're telling renderer to filter highest intensity samples, so in theory this should lead to faster noise cleaning, but it probably don't affect how long each pass takes to compute. If you're using pass count as render limit, then likely you won't notice any difference in render speed.

Will just render slightly smaller and enlarge in photoshop with a sharpen.... not the best but what can you do!

Even better option would be to use some AI upscaling program or service. Usually you can get much better quality compared to traditional methods.

[GeorgeK]

Hi,

I am rendering a complex scene and it is taking so long to render (even on farms) that it is eating into my budget for the project.

The problem is that it is made of thousands of glossy refractive tubes. Which is obviously slowing down the scene considerably. I am also going to ask around on 3ds Max forums for help in optimising the geometry but the majority of the slow down is the material itself. (It renders fine as clay).

I have created a material with no glossy refraction's and set to (thin) for tubes not directly visible.

I am just unsure how to simulate the look with a simpler material. The tubes need to catch the light and disperse it, I have also added self illumination to the ends of the tubes. But from my testing the slow down is obliviously mainly from the refraction. 

Any ideas? Or is this just going to be one of those projects haha!

Oof! Yeah not much you can do optimization wise only cheating but then again depends on the proffered render outcome.

[cgbeast]

Render with Vray...