Rendering speed tips for V-ray - Architectural Exteriors - Kuinka nopeauttaa V-ray rendausaikaa

(some of those are quite obvious, but I wanted to include all that I found useful; those tips come from my own experience, so some of them can be somehow wrong - please feel invited to correct me / discuss / give your solutions..)


1. DON`T USE TOO MANY LIGHT BOUNCES
usually first diffuse bounce is enough. You may try with one more secondary bounce, but not more... (for simple building, without many carved - semi-interior spaces) [render options -> GI settings]

2. DON'T USE TOO HIGH IRRADIANCE SETTINGS FOR RENDERING HUGE IMAGES
for image size of ~3600 pixels use irradiance settings like: min/max=-4;-3 (="very low" preset) with interp. samples=25 (to make things more smooth), or for the "superb" quality min/max=-4;-2"

3. ALWAYS SAVE YOUR IRRADIANCE MAP
may be useful to re-use it, when you'll be making some alterations to the image (incremental add is also useful then)

4. IF YOU HAVE A LOT OF RAM
you can speed things up by tweaking the vray system raycaster params. go up to 85(max tree depth) and down to 0,5 (face/level coef). but if your rendering doesn`t fit in your physical RAM memory, and gets swapped to the hard drive - then it`s no good - you'll have to lower these settings to the default -> 60;2 or even lower values, like 50;4.

5. DON`T ANTIALIAS TOO MUCH
for a huge images (as 3600 pix) it`s a good choice to set antialiasing to adaptive -1;2 with a tolerance of ~0,12. however some say that when using lots of fuzzy effects (like area shadows and glossiness) antialiasing mode should be switched to a fixed value or simple two level. from my experience in arch. renderings the adaptive mode works best in any case.

6. DON`T USE TOO MANY REFLECTION/TRANSPARENCY LEVELS
make it 2-3 max. this in most cases is enough [render options -> global switches]

7. SWITCH OFF THE "REFLECT ON BACKSIDE" PARAMETER
it slows things down generally and doesn`t have a great impact on the final look [in material editor -> vraymap/vray material]

8. REMEMBER ABOUT INTERPOLATED GLOSSIES
they take some time to render, but bring a lot of life to a huge flat, boring elevations and, of course, render a lot faster than direct computed glossies [material editor -> vray material -> reflection -> use interpolation -> reflect interpolation settings = -3;-1 or, for better "sharp" precision leave them at their default]

9. USING BUMP MAPS TOGETHER WITH INTERPOLATED GLOSSIES IS PAINFUL
and usually it produces lots of noises - try to avoid it

10. IF 3600pix IMAGE IS JUST TOO MUCH FOR YOUR MACHINE
make it 1600 or 2200pix and resize it to 3600 in PS/PP applying some directional sharpen. or try resizing it in program such as ssplinepro. no-one will notice )) ... until it`s printed on a laser printer ;(

11. REMEMBER THAT USUALLY IT`S A LOT FASTER TO DO SOME THINGS IN PHOTOSHOP/POST-PRODUCTION
than to wait three days for the output from MAX

12. ARCHITECTURAL GLASS IN VRAY
material = standard. reflection = vraymap with perpendicular/parallel faloff filter, opacity = 5, no glossies, material color as you like, shadow casting turned off in F2 objects menu, and one more thing - your glass objects should be rather boxies that extruded lines - vray sometimes has problems with the backsides of objects...
because we're not using refractions this glass renders quite quickly and in my opinion there's no quality loss (of course this depends on the building and type of glazing, but those are simple rules for simple buildings ;)
13. GLOSSY MATERIALS WITH HIGH SUBDIVISION VALUES MAKE SLOWER RENDERING
materialsreflection. keeping the Refl. Glossiness closer to 1.0 keeps the rendering time good, lowering them (for making blurry reflections) increases the calcutation time.
A good thing to try with glossy reflections is to use light cache for the second bounce and check the use light cache for glossies box. Sometimes the quality of the reflection is bad if it's too close to the camera but usually it's ok. That will save alot of time when rendering.

14. DISPLACEMENT MAPS EQUALS SLOW RENDERING
materials-->maps

15. TRACE REFLECTIONS
One tip for getting glossy highlights faster is the uncheck "Trace reflections" in the material options panel. Especially for smaller objects, like window mullions, you still can get the highlight effect that makes the material pop without wasting CPU time on calculating out reflections that likely won't make much visible difference.

16. rQMC SAMPLER
Noise Threshold under QMC Sampler can be kept at 0.05 for most scenes. making them 0.005 or more closer to 0.0 will substancially increases the rendering time.