The need for speed.....

[Robur]

Hi,

I still have loads to learn !!!! .... a deadline looms and my render times are way too high!!!! Any of you kind folk able to help tweek my settings .
The scene is simple 720x576 with diffuse material & egz glass only.
Model imported from ADT (autocad)
Light with a domelight HDR only.
Max enviro is a gradient map.
Vray enviro overides - black & Vray HDR map.
Secondary ray bias 0.001
Adaptive QMC 1/4 with Catmull-Rom
First bounce IM 1.0
Second bounce LC 1.0
IM set to medium HSPH 50 INterp 20
LC subdivs 500 - sample size 0.002 pases 4
QMC amount 0.85 noise 0.002 min samples 10 global sibdivs 4.0

These renders are taking 15mins !!!! In need to get this down to 2-4 mins if I stand a chance of getting the animationout on monday.....

Have I set things up badly or am I just expecting too much speed?

Thanks.

[jujubee]

Hi. The older EGZ glass (if you took apart his material) had subdivisions of 30 if I remember reading correctly. The latest versions of Vray use 8. Try that number instead cause that should work just fine.

Also, your global subs set to 4 multiplies all your settings by 4X - which increases quality at the cost of speed. Try lowering that back to 1, but you may want to add more samples to your LightCache in order to regain some lost quality.

[RErender]

Are you usng saved imaps and turning off LC for the animation? Along with what Juju said that should get it there.

[Robur]

Hi JuJu & RE ,

A great help..... now got it down to 3mins and that' without a saved map...... next step ...... save the map.

You guys saved my bacon - cheers

PS - why is LC not good for animation?

[RErender]

LC is good for animations! I only meant to turn it off when rendering with a saved irradiance map. The secondary bounces are stored into the imap when the imap is saved.

There are some instances when LC should be saved seperate from flythru mode and reused, mainly when dealing with glossy reflections and the use light cache method.

I hope you understand the ins and outs of using a saved imap, it needs to be calc'd and saved on one machine rendering every 50th frame or so, if the move is fast or circular/looping the step will have to be reduced.

There are a quite a bit of posts on saved imaps here and on www.vray.info, if it's not clear let me know.

[Robur]

Thanks Eric - I think I have now grasped saving maps for animations (thanks to Chris Nichols) - the penny is yet to drop with LC and how it interacts with IM !!!!....... something for later.

Can I ask a couple more basic questions ? - how do I make the shadows smoother at the edges..... (they are now coming from a sphere Vray light - with an HDRI in the Vray enviro) and how do I get a really nice architectural glass (not using egz glass now - just a basic vray material) - looking for a slightly blue glass that reflect the environment and the geometry around it ? I have swapped LC in second bounce for QMC.

Cheers.

[RErender]

For the shadows the penumbra is first dependent on the light size and then the light subs for quality.

For the glass, fog color will influence the overal color of the glass, dropping the refraction value from full white will make it more appearent. You can also adjust the diffuse and the reflection color towards blue. To help with the reflections you can cheat the reflection ior up to 2.0 to 2.5.

[Robur]

Thanks again Eric - I have now set the beast in motion - should be cooked by Monday..... Cheers & have a good weekend.

[percydaman]

QMC amount 0.85 noise 0.002 min samples 10 global sibdivs 4.0

these settings are overkill as well. the default .85 and .005 take much longer then they used to for negligible quality increase.

try .91, .009 global subdivs 1 and see how that does. might take some tweaking but might be a good start.

[DaForce]

curious....

Light with a domelight HDR only.
Vray enviro overides - black & Vray HDR map.

Isnt this kind of doubling up the HDR calculations?
Wouldnt you only need the domelight with HDR?

[RErender]

no, that way he can have a max enviro without it adding to the GI and have hdr reflections

[DaForce]

ah yeah, otherwise the max environment gradient would start adding into the GI... got it..

Sorry... slow and dopey this morning... damn colds

*sniffle*

[skogzort]

ReRender said:

"There are some instances when LC should be saved seperate from flythru mode and reused, mainly when dealing with glossy reflections and the use light cache method."

I'm fallowing a "walkthrough" tutorial now and I wondering when is this?
For purposes of deciding weather or not to re-use the LC with the IRmap for animations, what is meant by: “using glossy reflections”?

I have an animation with water in it. Both the reflection and refraction of the water material is set to 1.0 (the default) and fresnel is not checked. I’m I “using glossy reflections”? – I guess another way to ask is: When is a vray material not using glossy reflections? or what kind of reflection is not glossy?

Thank you very much for the help

[RErender]

Glossy is a strange term as it has taken on a definition in CG almost contrary to it's original definition. In this case I meant materials with a "refl. glossiness" of less than 1.0.

When your are using saved Imaps that where calc'd with LC and "Use light cache for glossy rays" checked, the GI/glossy solution for glossy materials is not saved in the imap. The reason to mention it is that if you do not have this scenario then all the GI info you need is stored in the Imap and it is not necessary to save and reload the LC.

[Robur]

Hi - an update to say thanks for helping me hit my deadline Came in Monday morning and it was done. In the end I used a saved IM from every 10th frame and LC for the second bounce - this was calc'd for every frame but even then the frames were poping out every minute or so - Next time I need to understand LC a bit better and learn how to set up a saved map for animations.

@ Eric - you are absolutely right about the black enviro overide - One thing that was also slowing the frames down was the HDRI domelight so I switched to an HDR environment which got me thinking - what is the advantage of HRD domelight?

Thanks again.