memory optimization

[arbolive]

hi, do any one know wy my computer is not using, all the (or a major part)memory while rendering? ( im using v-ray for rhino 3 the older version)

i've got 2 ram gigs and during the render, the program only uses 714 MB,

the weird thing is thst last week it used to grabb 1.86 gb while rendering.

(no any other program runing while rendering, only v ray and rhino)

thanks .

[dalomar_cg]

Re: memory optimization

V-Ray will only use as much memory as it needs for a render, so if its not using all of it, then it just doesn't need it. The amount of memory needed will change from scene to scene and even render to render depending on settings, resolution, geometry, materials and lighting. Basically I wouldn't really worry too much about it if vray still uses all of the available memory when it needs it. If you really want to use more of your memory, then increase the bucket size and that will cause Vray to use more memory. That may not speed things up though.

[arbolive]

Re: memory optimization

well this scene, took about 15 hours to get rendered, and, ive done more complex ones in 2 hours whith the same configuration, that confuses me. can you tell me more information about the bucket size snd where it is?
any link?


thanx

[joe_b]

Re: memory optimization

Generally, very slow renders are caused by over-brightness. The way V-Ray handles image sampling pays more attention to brighter areas than dark ones.

Also - configurations sometimes will not work in multiple different scenes the same way. Without the model or settings it is hard to say what the cause of this performance difference is. Does the scene make heavy use of refractive / glossy reflective materials? Is the lighting too bright, as I previously mentioned?

As I have mentioned in some other posts - the way V-Ray handles refractive materials has changed a bit between the RC2 and release ( if my memory is correct ). So perhaps this change in how we handle refraction is accounting for the different render times you are noticing. If you are using primarily simple geometric objects with refractive layers ( panes of glass, simple vases ) then maybe you can turn the max depth down from 5 to 2. That option is in the Global Switches portion of our options. But if you are applying refractive materials to complex or thick objects then turning down the max depth will probably just introduce artifacts into your rendering.

Hopefully some of this might have helped. If not - if you can spare your scene then maybe I can take a look and be more helpful.

[edit]
Just noticed your question about where the bucket size is. You can find that under the System tab. It controls how large the divisions, or buckets, are. It is possible to gain a little performance by optimizing the size of the divisions ( too many divisions will slow it down, too few will also slow it down ). However, I really doubt that bucket size will be the difference between 15 hours and 2 hours. Its worth a shot I suppose.

[Micha_cg]

Re: memory optimization

Also duplicate objects can cause a hard slow down. Most, if objects with transparency map are used and duplicated by an error. If objects must be used at the same place (for example intersections), than set the global bias at 0.0001 and it should help.

Try _seldup and Rhino will show you duplicated objects.

[dalomar_cg]

Re: memory optimization

Yea if the case is a 15hr render verses a 2 hour render then the issue is not the bucket size or your memory, but what is happening in the scene and what your setup is. You need to post details of each scene, because thats the only way to help figure out whats wrong. Also the memory isn't going to speed things up, its only going to cause issues if you run out. Even if you did adjust the scene so that it did use more memory, all of that would still need to be processed, which comes down to the speed and number of your processor. Post your details and then will be able to get to the bottom of this

[arbolive]

Re: memory optimization

sorry, i'd forgot that a've posted here, well yes in my scene there are a lot of reflection, refraction usage, here are both scenes , take a look please,

scene settings are:


water scene: IR + LC _caustics on_ color mapping, reinhard burn value 0.7 multiplier default_ image sampler: adaptive QMC: subdivs 60

( the water material: is bump maped_ refraction layer:translucency option checked on _ reflection layer: fresnel on. )


cinema scene: IR + QM(noise treshold 0.001 ) _caustics off_ color mapping, reinhard burn value 0.5 multiplier default_ image sampler: adaptive QMC: subdivs 40.



thanks for the replies ( any critiques about the work are welcome)

[arbolive]

Re: memory optimization

this render had more geometry an it took 2 hours to get done ( but here is not much usage or reflections/refractions)

[SreckoM]

Re: memory optimization

There is much more reflection and refraction in first picture, plus you have turn caustics on, and there is answer for much bigger rendering time. Reflection and refraction dramatically pump up rendering times.

[joe_b]

Re: memory optimization

Yes, glossies can add to render times. Without actually looking at your scene's geometry and options, etc, it is hard to say what the root issue is. I don't see anything there that should take 15 hours - even with the glossy reflection/refractions. Are you using a lot of area lights? Sometimes a lot of area lights can have a drastic effect on render time.

If you don't mind sharing the scene with me I can take a look. I understand if that is not possible.

[Micha_cg]

Re: memory optimization

Turn off caustics (!) and use IM+LC (use for glossy rays enable) could speed up.

What's your machine?

[arbolive]

Re: memory optimization

thank for the replies.

my machine specs: core 2 duo e6600 2.4,_ 2 ram gigs ddr2 800_ geforce8800 gtx video card_680i MoBo.

well and speaking about lighting, i used HDR for enviroment. For GI i used a piece of this image ( i cutted a section of the enviroment image ) with a blur filter ( thanks micha, for this helpful advice ), , then i used a point light to generate , some special reflections. and , if you see , under the wharf are lights in 3 places, in each place, there are a rectangular light and a a spot light.

thanks

[Micha_cg]

Re: memory optimization

Dual core and 2 hours for the second image (most diffuse/emitter materials and less reflections) - I don't understand. Did you test the suggestions (caustic off ... )?

[arbolive]

Re: memory optimization

yes in the second image, caustics where unchecked, noise treshold of 0.001.

[Travis Serio_cg]

Re: memory optimization

the black chairs seem to have a fresnel reflection layer to them. I have a feeling it may be to blame.