The impact of render elements in rendertime

[marcelo fernandes]

Hey, Guys.

First of all, let me excuse myself if this topic has already been brought up.

 

I have had a couple days of freetime in between assignments. For 2 days i decided to improve my MaxStart file, where I added VraySun linked to HDRI rotation, all the nice viewport tweaks and also my most used render elements.

 

After that, I saw my rendertimes go skyrocketing. I've been doing some quite specific jobs, so i always thought it was something related to a certain material or whatever.

 

Now, starting a new assignment i am doing some very basic renders-in-white and i got it. I just made a quick are render of a part of my image and surprise, surprise.

-render elements off: 8.5s

-render elements on: 1m,30.6s

 

This is huge and it's the first time i stop to think that render elements could have a dramatic impact on rendertimes.

 

 

The vrayextratex ones are.

Vraydirt

Vraydirt + a texture on radius for dirty walls

Vraydirt with invert normals activated

the last two are bitmaps that i pass over the entire scene.

 

I mostly work on realworld units so that i can use these last vrayextratex ellements to give more texture to the images in photoshop

 

 

Does anyone know about the impact of each of the elements? Is it my vrayextratex ones?

If there is not a study on this i will be more than happy to, once i have some free time, do it myself. I can tell you how much more each render takes with each extra element and share the results with you guys.

[Francisco Penaloza]

Not sure if there is a study already, but render element increase render time and also RAM usage during rendering.

We use a lot of them, mostly multi-mats but I can tell you that all those AO and drit passes increase the rendering time more than a Mat ID, why you need so many of them? well that's up to each artist but multi-mats and Wire color uses antialising, so they use more memory than VRay ID for instance. but even with that they are not as heavy as Dirt or AO, Light select uses more RAM compared to Mat ID.

All these affect in small quantities, but when you add too many of them, it will make a difference.

Any ways you need to think, if this "extra" rendering time it is worth instead of re-render the whole scene to do unexpected changes.

I rather have everything at the first try.

[martinhoura]

render elements themselves don't add very much rendering time since vray is rendering them anyway at any given time, albeit in the background - think of adding them as turning the visibility on and off. it does use more ram though, depending on the resolution.

 

the reason why your rendertimes are huge is because you are basically rendering 6 images at the same time (1: the ,beauty pass [and all the reflection/gi/zdepth/etc passes] + 5 ao renders). if you want it to be faster than delete your extratex elements, why do you need 5 of them is beyond me anyway

[Nic H]

why do you want 6 millions extra tex with vray dirt elements

they are whats slowing your renders down

[marcelo fernandes]

I actually use these extratex almost everytime in photoshop. I've made a small test now and you guys are completely right.

-12.1s with all elements on

-6.2s with all elements but the extratex ones

-6.3s with elements off

Problem solved. I will probably make a render preset to apply these textures in a second render with lower settings.

Thank you guys