rectangular area lights?And interior lighting(<=>MR portal light

[dbukovec]

sorry bringing this here always, i'm just curious how they do it, this scene renders in 20 sec in modo. I really dont knwo how they do it, view dependent irradiance caching or something, but i'm jelaous a bit.

[DaJuice]

in fact i thought if i restrict the irradiance to the material it would be more efficient (i know in this scene there shouldn't be much of a difference since we have only one material but that was the idea) so what do you think about that.

Hmm, I don't think it will be more efficient, and just makes the scene setup more complicated when you start getting multiple shaders, each with their own irradiance nodes.

i have a problem with your scene, and i played around with it and i couldn't solve it ... it's rendering very dark :S, i even kept pumping up the directional light intensity to 5000!!! and ntg has changed (i turned off the irradiance caching and tried, also no change) ... soooo i'm really puzzled here ...

The render is gamma corrected. If you look at the mantra node, I've set the gamma to 2.2 (and gamma is one of those parameters you have to add manually). On a real project that's not where you want to do your gamma correction, but for little test renders and file attachments with no outside textures and post work, it's okay. SYmek put up a nice explenation recently: http://forums.odforce.net/index.php?showto...amp;#entry59437

one more thing can you please DaJuice explain to me a little bit about the irradiance cache? especially when is it used and with which setups?

The default interface for Irradiance caching in the Irradiance tab looks a bit weird. What I mean is, the actual cache setting parameter and field are missing by default. Now someone correct me if I'm wrong, but without those two settings it doesn't actually allow you to cache anything, does it...? In any case, you can add those parameters back in:

When you render in Write or Read/Write mode, mantra writes to the cache file, and subsequent renders lookup the cache file to speed things up. If I remember this right, the cache is view-dependent, so as you render the scene from different angles more data gets written to it. If your scene and lighting are basically static, it can cut down render-times by a quite a bit.

Edited May 8, 2009 by DaJuice

[nmn]

Thanks for the answers DaJuice

The render is gamma corrected. If you look at the mantra node, I've set the gamma to 2.2 (and gamma is one of those parameters you have to add manually). On a real project that's not where you want to do your gamma correction, but for little test renders and file attachments with no outside textures and post work, it's okay. SYmek put up a nice explenation recently: http://forums.odforce.net/index.php?showto...amp;#entry59437

In fact i know very well about the gamma, since i'm very good with MR you know ... but seems that's not the problem, basically your gamma is set to 2.2 so that should make the image brighter and what i'm getting is an almost balck image and till now i didn't figure out why :S:S, normally if i just open up your file and render it i should get the same result as yours no ?

thanks for the explanation about the irradiance cache, from what you said i feel it's very similar to the MR final gather pass?especially that it's view dependant and it adds to the file in the read/write mode.. or am i mistaken?

though one thing i want to know about it also, is WHEN it's used, i mean if you for example: create a scene, create a cube inside it, enable irradiance cache and hit render, it wouldn't be used, coz there is nothing using irradiance in the scene right ? so by WHEN it's used i mean, for example when you use a vex global illumination node, when u use irradiance node inside material ...etc those cases ... any clarification about that point ?

Ah one more thing, in fact i found another reason why i would want to use irradiance inside the material, it's that up untill now i didn't find a way to turn off the indirect illumination on some specific object, like you would do for example for light linking or shadow linking ... so is there a way to turn off irradiance cast and irradiance receive for specific materials WHILE using for example vex Global illum ?

Thanks again

Edited May 8, 2009 by nmn

[DaJuice]

In fact i know very well about the gamma, since i'm very good with MR you know ... but seems that's not the problem, basically your gamma is set to 2.2 so that should make the image brighter and what i'm getting is an almost balck image and till now i didn't figure out why :S:S, normally if i just open up your file and render it i should get the same result as yours no ?

That's strange, no idea why it would do that tbh... Which build are you using?

so by WHEN it's used i mean, for example when you use a vex global illumination node, when u use irradiance node inside material ...etc those cases ... any clarification about that point ?

Ah yes, it's for use with Irradiance (and also AO I think).

so is there a way to turn off irradiance cast and irradiance receive for specific materials WHILE using for example vex Global illum ?

Yes, every object has a Light Mask field. Go to that field and remove the vex_gilight light template.

[nmn]

That's strange, no idea why it would do that tbh... Which build are you using?

10.0.249.3, so you confirm that i should get your result if i just open up the file and hit render ?

it's frustrating me a little, since i checked out every possible thing and didn't find any solution,

and also every file i create on any one of the machines here (3 machines) the irradiance times are too long not even comparable to yours

and one more strange thing, your file is rendering so dark that's true but it's taking almost a time comparable to yours !

so i'm like ....

thanks for the vex gi light link tip i didn't think of that one

[DaJuice]

10.0.249.3, so you confirm that i should get your result if i just open up the file and hit render ?

it's frustrating me a little, since i checked out every possible thing and didn't find any solution,

and also every file i create on any one of the machines here (3 machines) the irradiance times are too long not even comparable to yours

and one more strange thing, your file is rendering so dark that's true but it's taking almost a time comparable to yours !

so i'm like ....

thanks for the vex gi light link tip i didn't think of that one

Yep, you should be getting the same render. I have no clue why it's not... Can you attach a pic of what you're getting when you render?

I would say try downloading a newer build. Good idea in any case since there have been many bug fixes.

[nmn]

the slow down render issue is on the three machines (2 of them are with 10.0.249.5 and one-the one on which i tried your scene-has the 10.0.249.3)

so i'll try your scene with the 10.0.249.5 (i can't get any newer than that with apprentice ) and post a pic for you.

besides now i have another question about GI per objects , lol i always have lots of questions , can you specify an AMOUNT of irradiance per object ? or it's only 0 or 1 ?

Thanks a lot for your help DaJuice i appreciate it really, hope we can get this solved ...

Edited May 8, 2009 by nmn

[DaJuice]

i can't get any newer than that with apprentice

http://www.sidefx.com/index.php?option=com...&Itemid=208

Login with forum id and scroll down to daily builds.

can you specify an AMOUNT of irradiance per object ? or it's only 0 or 1 ?

With the light mask example it's either on/off I'm afraid. If you really want to do it at shader level I think you have to watch out how materials with irradiance nodes interact with each other, as far as how the lighting will end up looking. Last time I tried it I got weird results...

[nmn]

Thanks for all the info , especially for the link.

well i'll try and do some more tests, with your scene and for the speed issue with the newer builds ... and i'll be back to you, for help ...

Cheers

Edited May 9, 2009 by nmn

[nmn]

Ok so i got the the 10.0.273, i did some tests on it, your scene renders as it sohuld ! finally !

and i recreated the scene and i test rendered and guess what ?! it rendered a looooot faster finally !!

i won't call it done until i do some more tests though but apparently up until now it's good !

Thanks

Edited May 9, 2009 by nmn

[DaJuice]

Excellent, that's good to hear. :thumbsup: