Long render times for interior architectural renders

[alexyork]

It's just tight deadlines, issuing anything between 5 - 15 Hi res renders daily. Its easy to see why even the slightest increase in render time is a bit of a problem.

You're right that certain scenes and settings just need more time - but it's time we don't have !

There's a careful balance to be made between spending time optimising your scene and just using that same amount of time in render. For me it comes down to what I'm doing - if it's animation then absolutely it's worth spending a lot of time optimising to get frametimes down to keep render costs down for the farm. If it's stills then for me an overnight render is perfectly acceptable across a few machines in DBR at 5k (talking about a complex interior with loads of lights and reflective surfaces etc.).

It just depends on what I'm doing and what kind of deadline I have.

In your example of producing 5-15 high-res images every day.... if you're pulling in that kind of huge workload then surely it would be best to just invest in another load of rendernodes and cut your rendertimes in half? In many cases, why spend 2 hours optimising a scene when you will only save 30 mins of rendertime? If you're talking about animations it's different of course, but for regular old day-to-day stills I find that more often than not I'd rather spend that time working on another scene/job and use that time rendering on my nodes instead.

It's all about finding the right balance for the job.

[AlexP]

Yeah, although I'm finding diminishing returns on more render hardware now to be honest. In order to cut times in half we're talking serious investment, more machines come with their own problems as well, more licenses, more cooling, more space !!

Then its the fact that everybody needs the nodes available all day to be able render drafts and tests etc etc
Clients are expecting more and more drafts, sometimes up to 3 sets throughout the day, at at least half the final resolution.

Im definitely on the optimizing side of the fence, I like efficiency! I always spend time optimising, but then every minute I save doing that I end up filling with an additional effect or higher quality finish so it balances itself out in the end more or less.

Probably to need to re-explore render farm services... not sure they are cost effective for stills though.

[vlado]

I will zip a scene tomorrow and get it over to you. It will be too big to email - how else can I get a large zip file to you Vlado?

Email me and we'll get you FTP info to upload it.

Best regards,
Vlado

[vlado]

I am interested in any slowdown associated with the ColorCorrection Map though as I use them a lot (but then almost everyone must do).

In a particular scene that we profiled, 30% of the render time was spent inside the ColorCorrection texture (in that scene, almost every bitmap was passed through a CC map). Some more percent were spent in procedural Noise textures and such like. That's why I said I need an actual scene to look at - it's hard to figure this stuff in advance.

Best regards,
Vlado

[alexyork]

In a particular scene that we profiled, 30% of the render time was spent inside the ColorCorrection texture (in that scene, almost every bitmap was passed through a CC map). Some more percent were spent in procedural Noise textures and such like. That's why I said I need an actual scene to look at - it's hard to figure this stuff in advance.

Best regards,
Vlado

That's very significant indeed!

[rikou]

In a particular scene that we profiled, 30% of the render time was spent inside the ColorCorrection texture [...]
Best regards,
Vlado

Damn, I have to think again about it... I use a lot of CC

[alexyork]

Looks like we need a VrayColourCorrect material

[rjohnson33]

Looks like we need a VrayColourCorrect material

Indeed! or some viable alternative if a 30% consumption is a possibility. I take it this is some sort of failure in the coding of the ColourCorrect map or is a significant time loss going to be inevitable when performing all of those adjustments on the fly?
I'd imagined that it would perform all of the adjustments at the beginning of the render and hold those in memory but I suppose that negates the memory-saving aspect of having fewer source images.

I thought about the VrayHDRI loader but there is no control over Hue/Saturation. It would be great to have an image adjusment map with more generous controls (a bit like what we now have in the VFB in Vray 3) - as long as there were no big negative impact on render times associated.

4k wide would be ideally 6-8 hours on a single i7, up to 12-15 for some particularly elaborate ones

Similar renders are honestly about 5 times longer than this for me. I must be cursed!

[tricky]

In a particular scene that we profiled, 30% of the render time was spent inside the ColorCorrection texture (in that scene, almost every bitmap was passed through a CC map). Some more percent were spent in procedural Noise textures and such like. That's why I said I need an actual scene to look at - it's hard to figure this stuff in advance.

Best regards,
Vlado

Wowsers! I use quite a few CC maps. I often use them within a BerconTile/Multimap texture too which can have many high resolution textures inside (for timber floors, marble walls, brick walls etc). This could be a big potential slowdown in this case. I have just emailed you and look forward to your findings.

[vance3d]

Vlado

I think its great that you can see where render time is going to that level. Any chance of including some kind of diagnostic tool that would allow a render to be broken down in a "percentage of time per process" basis? I would imagine is goes way beyond what is revealed in the vray info window even at its most verbose setting. I'll try to reduce my dependence on cc textures in the mean time for sure.

V Miller

[hoppergrass]

Looks like we need a VrayColourCorrect material

Second that suggestion

[windowlicker]

That would be awesome. Or a VrayColorCorrect-map, preferably. CC is a good thing, but I never ever use it due to the slow-down. I edit textures in PS whenever I have to.

As for workflow, I always use a simple IM/LC setup defined in a "template" file. Render settings at medium-ish quality: DMC 1/4, noise thres 0.01, IM -3/-1 50hsp, 1000 LC samples, use glossy rays... Lights and materials with a decent amount of samples according to dispersion/glossiness. It works as a decent base, and it does the job if you're on a tight deadline.
For high-end jobs, just crank up DMC to 1/8, noise thres ~0.004, IM -3/0 75hsp, 2500 LC - add some detail enhancement with a small radius and multiplyer. This works for most scenes. I usually render at 5000x3000px and on a single i7 it finishes over night. There might be some noise here and there, but the client never ever... ever notices that. So, in the end, working with a setup that minimizes tweaking, and works in 99% of the jobs saves a lot of time, headache and money.

[tricky]

For high-end jobs, just crank up DMC to 1/8, noise thres ~0.004, IM -3/0 75hsp, 2500 LC -

This is the type of thing that I too would have done in the past. However, it has become apparent, through several users explanations, that upping the max DMC sampler from 4 to 8 like this can actually increase the overall noise as all values are divided by 8 (squared) rather than 4 (squared). This is the bit that is always counterintuitive (to me at any rate).

Of course, as I have said many times, it is always a balancing act between render time and render quality and workload largely dictates where the weighting should be placed. I'm on a continual mission to increase quality and am prepared for an increase in render time to a point. The GW approach (sorry for that term Grant - I know its not all you, and it isn't intended to be derogatory) so far has lead to overly massive hits in rendertime for my type of work (high resolution, high quality archviz interiors) and workload.

I am looking forward to a review of one of my scenes which I have issued to Vlado as he suggested. Could be quite revealing (and hopefully it will reveal some of the stupid errors I have no doubt made!).

[Morne]

Looking forward to feedback on this one. Please keep us updated...

[tricky]

Looking forward to feedback on this one. Please keep us updated...

Will do. I am preparing myself for some embarrassment