Tree optimization

[glorybound]

Yes.. those global scripts will get you in trouble almost every time - should I turn filtering back on for everything? How do I know what should, and what shouldn't have filtering on?

No, the scene doesn't have opacity maps; however, even if it did, it makes sense to turn filtering off for the opacity map only. For Bobby's scene, the disabled filtering actually increases render times, as more AA rays need to be shot.

Still looking around the scene though...

Best regards,
Vlado

[voltron7]

Yes.. those global scripts will get you in trouble almost every time - should I turn filtering back on for everything? How do I know what should, and what shouldn't have filtering on?

I only turn it way down if the texture looks too blurry. Turning off 100% seems to often give me bad results.

[vlado]

For the trees specifically, it is the 180 GI subdivs that are killing them; those are good for the relatively flat surfaces of the building, the road and cars, but not for the trees as they need significantly more AA. One easy way to reduce the render times without touching the rest of the settings is to decrease the GI subdivs multiplier in the V-Ray object properties of the trees to something like 0.05 or similar (you'll have to play with the number for a good value).

However as I've said many times before, a more balanced approach closer to the universal settings might work better. Still trying a few things out; will let you know how it goes.

Best regards,
Vlado

[voltron7]

So far, I have found that trace reflections was enabled on the leaf material.
I made some tests on your general scene optimization and got rendering time to about 30-40 minutes for that frame. (No motion blur.)
When I opened your scene and rendered, it was saying something like 12 or 22 hours...the buckets did not go.
Also, the trees are now rendering as quickly as the rest...maybe the windows are a tad slower.

edit: Okay, the grass is now the "slowest" but still about real time.

Also motion blur had 100 samples but I don't know squat about M-blur.

[glorybound]

is there a script to reverse the damage? I tried one, but it failed.

I only turn it way down if the texture looks too blurry. Turning off 100% seems to often give me bad results.

[glorybound]

For the trees specifically, it is the 180 GI subdivs that are killing them; those are good for the relatively flat surfaces of the building, the road and cars, but not for the trees as they need significantly more AA.
Vlado

When I hear more, I think higher than 180, but you are saying less, correct? I was raising it until I stopped seeing red in the sample rate. So, are are saying drop it down to its default, or 8 subdivs?

[glorybound]

When mine starts it also shows a 30 minute estimated render time, but once it gets down to the trees, it jumps back up. I am tweaking the trees and turning off motion blur for now.

So far, I have found that trace reflections was enabled on the leaf material.
I made some tests on your general scene optimization and got rendering time to about 30-40 minutes for that frame. (No motion blur.)
When I opened your scene and rendered, it was saying something like 12 or 22 hours...the buckets did not go.
Also, the trees are now rendering as quickly as the rest...maybe the windows are a tad slower.

edit: Okay, the grass is now the "slowest" but still about real time.

Also motion blur had 100 samples but I don't know squat about M-blur.

[voltron7]

is there a script to reverse the damage? I tried one, but it failed.

Hmmm, not aware of one, but that would be nice.

[glorybound]

this worked
(
local theBitmaps = getClassInstances bitmaptexture
for aBitmap in theBitmaps do
(


aBitmap.coords.blur = .01
aBitmap.filtering = 2 --0 is Pyramidal, 1 is Summed Area, 2 is None
)
)

Hmmm, not aware of one, but that would be nice.

[vlado]

Bobby, is it ok to post some comparison images here?

Best regards,
Vlado

[glorybound]

yes, please!

[3DMK]

For the trees specifically, it is the 180 GI subdivs that are killing them; those are good for the relatively flat surfaces of the building, the road and cars, but not for the trees as they need significantly more AA. One easy way to reduce the render times without touching the rest of the settings is to decrease the GI subdivs multiplier in the V-Ray object properties of the trees to something like 0.05 or similar (you'll have to play with the number for a good value).
Best regards,
Vlado

This makes a huge difference to your render times regarding trees. I annoyed vlado heaps about implementing this into Vray & it has made a huge difference to rendering tree/plant heavy scenes. Before that I would often render different areas of a scene using incremental add to map with different subdivisions. It saved a lot of render time but required me sitting there & setting it up ....& waiting..& too much time.
Per-object GI subdivisions is the perfect solution & gives the best results for trees & plants, although it can also be used for everything else. I use it a lot on white ceilings..I often double or triple the GI subdivision amount for these objects & the result is never any more splotchy areas from not enough GI subdivision on ceilings which is where it's most noticeable.

I have also found that IF you are using opacity maps then try & keep them as small as possible & ALWAYS keep them pure black & white...Never use an antialiased edge on an alpha....if the alpha has grey in it then the renderer has to deal with partial opacity & this seems to really slow it down. especially when it is ray-tracing 30 alpha maps per pixel!!!! To fix this -- go to photoshop & do a threshold to change it to black & white.

Hope this helps
Cheers

[vlado]

I have also found that IF you are using opacity maps then try & keep them as small as possible & ALWAYS keep them pure black & white...Never use an antialiased edge on an alpha....if the alpha has grey in it then the renderer has to deal with partial opacity & this seems to really slow it down. especially when it is ray-tracing 30 alpha maps per pixel!!!! To fix this -- go to photoshop & do a threshold to change it to black & white.

For the nightly builds we've actually added some methods for dealing with this directly in VRayMtl.

Another slowdown point for this scene besides the trees is that "Affect shadows" is not turned on for the glass materials. This causes the interior of the building to be lit entirely with caustics from the environment map which needs a lot of GI samples to clean up.

Best regards,
Vlado

[glorybound]

I am still a little unclear. Do I need more subdivisions on my trees, or less? Currently, to get rid of red in the sample map, I have it set at 180. So, do I go up with a higher number or down with a smaller number? Vlado implied that 8 was a good starting point.

This makes a huge difference to your render times regarding trees. I annoyed vlado heaps about implementing this into Vray & it has made a huge difference to rendering tree/plant heavy scenes. Before that I would often render different areas of a scene using incremental add to map with different subdivisions. It saved a lot of render time but required me sitting there & setting it up ....& waiting..& too much time.
Per-object GI subdivisions is the perfect solution & gives the best results for trees & plants, although it can also be used for everything else. I use it a lot on white ceilings..I often double or triple the GI subdivision amount for these objects & the result is never any more splotchy areas from not enough GI subdivision on ceilings which is where it's most noticeable.

I have also found that IF you are using opacity maps then try & keep them as small as possible & ALWAYS keep them pure black & white...Never use an antialiased edge on an alpha....if the alpha has grey in it then the renderer has to deal with partial opacity & this seems to really slow it down. especially when it is ray-tracing 30 alpha maps per pixel!!!! To fix this -- go to photoshop & do a threshold to change it to black & white.

Hope this helps
Cheers

[glorybound]

Okay. I think I am getting it... Sometimes you have to ignore the sample rate map. By turning down my tree subdivs, to something around 8, and lowering the GI subdivs multiplier in the V-Ray object properties further, my trees now render fast. But, having said that, they are red as heck on the sample rate map.