Weak spots of VRay

[Oleg_Budeanu]

Hello everyone !
We all love VRay for it's flexibility and speed. We use it in production, gamedev, archviz and many more CG domains.
Though as any software which is in constant development it has weak spots and i wanted to collect them here. I want this thread to become not a bug report section, but collection of tips and tricks how to make your renders faster and with predictable results.
I am mostly architectural visualization artist, and my findings are mostly related to this domain.

First thing i've found recently is new probabilistic lighting and VRayIES lights.
Using them together gave me weird results like "grey" lighting and incredible amount of noise, which is really hard to clean.
So switching off probabilistic gave me totally different render image and almost noise free with AA 1-6 and Noise threshold about 0.06. With probabilistic i should've gone up to 1-16 and 0.005 !
I have about 200 VRayLights and about 50 IES lights, lighting up trees and etc. I understand that this should be used in specific situations, but it is on by default, meaning that it works everywhere as default.

Second weak spot i've found is VRayLightMtl. It gave me incredible noise in glossy reflections (~0.7 in material) and GI. Turning on Direct Lighting for material resolved issue a bit, but the best scenario is to avoid them and use VRayLights where possible - clean and fast results.

Hope this topic will help developers and resolve issues we might have.
If anyone has any findings of weak spots - i will be happy to update this post to keep track of those things.
Thanks !

[vlado]

Thanks for the feedback! We are aware of these issues and we are working on resolving them. Expect some improvements for the next service pack.

Best regards,
Vlado

[Oleg_Budeanu]

Thanks for the feedback! We are aware of these issues and we are working on resolving them. Expect some improvements for the next service pack.

Best regards,
Vlado

That's great !
Also i've noticed one more thing. If i have for example 3 separated rooms on exterior, i light only first and last - if i use probabilistic lighting - it will throw samples in the one between them, lighting it a bit also (but in a weird way). This thing is very obvious if you have 50 rooms like that separated.
But i think you are aware of that also

[vlado]

Yes, that will be fixed as well.

Best regards,
Vlado

[Oleg_Budeanu]

Another thing i've noticed is really slow performance of VRayProxy "show preview from file" option.
I know that there are several options for previews when you convert model, but i converted curtains into VRayProxy with medium preview option and 10k polygons.
In viewport i have about 6 curtains VrayProxy instances and viewport performance drops significantly.
Changing preview mode to bounding box makes it almost 10x faster ! 7 FPS vs 60 FPS.
Also helps preview from file (faces). Improves performane to 60 fps also.
I am missing something ?
I have 16GB Ram, SSD, and GTX 860M.

[vlado]

Hm, that's odd. If you can send the proxy to support@chaosgroup.com we will be able to investigate what's the problem.

Best regards,
Vlado

[squintnic]

Another thing i've noticed is really slow performance of VRayProxy "show preview from file" option.
I know that there are several options for previews when you convert model, but i converted curtains into VRayProxy with medium preview option and 10k polygons.
In viewport i have about 6 curtains VrayProxy instances and viewport performance drops significantly.
Changing preview mode to bounding box makes it almost 10x faster ! 7 FPS vs 60 FPS.
Also helps preview from file (faces). Improves performane to 60 fps also.
I am missing something ?
I have 16GB Ram, SSD, and GTX 860M.

i get this as well - kills my files when its on
using 2014 on a gtx980Ti
ill get a file together

[Oleg_Budeanu]

Thing is that it is not a specific proxy file - it's all of them.

[vlado]

Thing is that it is not a specific proxy file - it's all of them.

I would still like to get an example, in order to get an idea of the number of triangles and other information that you might have in your proxies.

Best regards,
Vlado

[joconnell]

I've got similar here vlado, got a very large scene which uses mip mapping and it's pretty bad in terms of using the cpu.

[vlado]

I've got similar here vlado, got a very large scene which uses mip mapping and it's pretty bad in terms of using the cpu.

I'm not sure how we jumped from proxies to mip-mapping here, but feel free to send me a scene for investigation to vlado@chaosgroup.com or to open a new thread. It very confusing (i.e. I really hate it) when people just add random unrelated stuff to existing threads.

Best regards,
Vlado

[joconnell]

Sorry, similarly I've a scene which is made with a tonne of proxies but also mip mapping on top of it.

Noted on the thread though, will think of each thread as a ticket

[Oleg_Budeanu]

Well i did not want to make this thread as a ticket I wanted to gather "weak spots" of our favorite render. Some not really obvious things you can notice and can be improved.

[vlado]

Well i did not want to make this thread as a ticket I wanted to gather "weak spots" of our favorite render. Some not really obvious things you can notice and can be improved.

I appreciate you taking the time to do it! However it's very confusing for us to follow such uber-threads, especially when multiple people jump in with other comments. If you want us to pay more attention and understand things better, it would be best to post separate threads. It helps us a lot when we get to actually implementing stuff. Thanks again!

Best regards,
Vlado

[Oleg_Budeanu]

I appreciate you taking the time to do it! However it's very confusing for us to follow such uber-threads, especially when multiple people jump in with other comments. If you want us to pay more attention and understand things better, it would be best to post separate threads. It helps us a lot when we get to actually implementing stuff. Thanks again!

Best regards,
Vlado

Got you, Vlado. Thanks for paying attention into this and looks like proxy issue is being there not only for me. As i will be able to send couple of proxies - i will.