going back to 1-45

[alkis]

hi all
i very rarely post here mainly cos of workload and NDAs BUT i have been around for almost two years.
On monday night when the latest beta was made available i thought that finally the time had come to get an almost perfect renderer for the jobs we do, especially after a 3 month or so gap that has followed the release of 1-45. The bugs on it were plenty so one would have thought that the main issues were fixed.
So i went ahead and downloaded the latest and decided to replace the 1-45 version which we have already started using for production mainly because of the proxy.
I am afraid i ll have to go bak to that version as whatever i do with the new one is always at least 3 times slower than before and i am only using irmap and qmc, no lightmap.
here are two images that show that (work in progress)


settings: all default apart from
min -4
max-2
hsph 20
prim irmap mult 1
sec qmc mult 0.5
qmc subd 3, sec bounces 1
The scene was made in max7 and the materials are mostly multisubs Standard and vray (1-46) mats for all the glass
Trees are vray mats( 1-46) with alpha in op.
There are no glossies in the scene.
I also have been completely unable to render the same scene with lighmap regardless of the combination of settings i used because it always freezes before it even starts the calculation.
Lightmaps with teapots work great but i dont think our clients would like teapots insted of buildings(although i wish they did).
Any ideas or comments would be really appreciated.
regards
alkis

ps. i do not wish to upset anyone and i am very happy with vray ,
i only want to get my old rendertimes with this a fixed 1-45 version whatever its name might be

[Long John]

lightmaps seem to be a big problem in this build.

i have noticed severall freezes the last days when i raise subdividisions over a certain value or some scenes won´t render at all with lightmaps.

together with the reflection bug for glas materials this makes 1.46.04 useless for us.

[natty]

Long John ...he isnt using Lightmaps...

Alkis ... as far as i know the newer version takes more samples than the last build ... show me a screen shot of your setting's please, all your settings...

[natty]

also your Rendered Primative's are @ different value's ... why is that ?

[alkis]

hi guys
thanks for the replys
natty: here are the settings
[img]ftp://80.176.192.46/settings.jpg[/img]
i dont have a clue about the primitive count
its exactly the same scene
another bug maybe?...

longjohn: light map , when it works is the coolest and fastest addition to vray . i havent been using it for production up to now because most of my mats are standard and now that i can use it it freezes up.
i ll continue to try and figure it out though as i can spare two more days on testing and upgrading

as mentioned in other posts it would be great if there was an extensive list of changes between version and maybe some quick tips for optimisations and different settings
thanks
alkis

[vlado]

Do you have a dual-processor machine? If yes, then I think the difference in render times comes from the Dynamic geometry option. You can try to render with Static geometry and see if there is any difference (if all the geometry fits into the memory, of course).

In 1.45, each rendering thread had its own geometry pool, where is in 1.46, all threads share the same geometry which means that when one of the processors loads geometry, the others must wait for it. If this needs to be done often, processors waste more time waiting for each other than doing any actual work. It's one of them memory/speed issues. It's not a bug, so there is nothing to fix (if this is the problem, of course).

As for lightmaps, they will freeze (cycle infinitely) when you have opacity-mapped standard materials; this is what I managed to find out. In that case, using VRay materials does the trick.

Best regards,
Vlado

[alkis]

vlado hi
thanks for the reply
specs : dual xeon 3.2 , 2gb RAM with 3GB switch enabled
i have made a render with static geometry which is significantly faster but still twice as slow as 1-45
[img]ftp://80.176.192.46/images/1-46-a1-static.jpg[/img]
if all threads now share the same geometry and it causes a problem with dual machines when you are using dynamic does it mean you can never use dynamic cause it ll always be slower?
thanks for the light map suggestions, i ll do some more tests and report back any further probs
thanks again for your time and effort
regards
alkis

PS vlado: do you have any idea why the primitives count keep on changing on the same scene if i use different methods of rendering or different setups
should i ignore it or could it be part of the problem

[vlado]

Do you have any VRay displacements in the scene?

The primitives change because with the dynamic geometry option, some geometry may never be loaded, if it's not needed. Using static geometry will always give the same primitive count (unless you have displacement or fur, which always create dynamic geometry).

if all threads now share the same geometry and it causes a problem with dual machines when you are using dynamic does it mean you can never use dynamic cause it ll always be slower?

Well, the purpose of dynamic geometry was to save memory, more than anything. The 1.46 build uses even less memory for dynamic geometry on dual machines than 1.45, although sometimes this may be at the cost of rendering time.

Best regards,
Vlado

[alkis]

nop no displacement

Well, the purpose of dynamic geometry was to save memory, more than anything. The 1.46 build uses even less memory for dynamic geometry on dual machines than 1.45, although sometimes this may be at the cost of rendering time.

that makes sense but the differences in render time are way to big to justify something like that

thank you again for your time and explanations
regards
alkis

[vlado]

Well, in your scene the slowdown is probably not only because of the dynamic geometry; have you tried comparing the number of samples in the irradiance map (as stated in the Irradiance map rollout)?

Best regards,
Vlado

[alkis]

hi again
here are some of my findings
the number of samples is as follows
vray1-46 :29161 samples - times as above (8min)
vray1-45 :21033 samples - times as above (4 min)

thats with the settings as above

after that i tried another test in 1-45
changed the min max and hsph subd to -3 -1 and 30 accordingly everything else exactly the same
this gave me the following image at a still a faster time than 1-46
[img]ftp://80.176.192.46/images/1-45-a2-min3max1.jpg[/img]
now the number of samples for that are........
...70511...
which is more than twice the amount of 1-46 render ( and still faster)
this is very interesting and even more puzzling
i hope that we can reach the bottom this
regards
alkis

[vlado]

You can also take a look at the number of rays that were cast by VRay in the VRay messages window to see if there is any difference (it says Number of raycasts: XXXXXXX after each frame).

Best regards,
Vlado

[alkis]

vray 1-46 : 45085158

vray 1-45 : it doesnt give me a number. the message window is below
[img]ftp://80.176.192.46/images/vraywindow.jpg[/img]
both dynamic and static options have the same messages in that window
regards
alkis

[Long John]

Long John ...he isnt using Lightmaps...

Alkis ... as far as i know the newer version takes more samples than the last build ... show me a screen shot of your setting's please, all your settings...

also have been completely unable to render the same scene with lighmap regardless of the combination of settings i used because it always freezes before it even starts the calculation.


must be someone else then.

[natty]

Just pointing out that he wasnt using lightmap .... i also have problems with lightmaps ..