i am loosing it...

[xeunox]

i know this is a complete and utter noob question, but i am totally loosing it with lighting for interior scenes using mentalray. ARTIFACTS EVERYWHERE, i have done all the usual stuff like deleted/recalculated the fg numerous times on numerous files. i have gone into a total flatspin because i cannot get it to work and i have since tried to add and remove speckle reduction with no effect, removed and added various lighting systems, tried it with and without global illumination and and and and...... i'm loosing it, help would be appreciated. using mr photo exp fyi, SKYPORTAL A HOAX!

[Tommy L]

ooooo, that looks nasty. What version of MR?

[xeunox]

max 2008, mr 3.5 i think

[Tommy L]

MR in Max 2008 is fantastic and (for the first time) quite logical. Take all of your lights out, assign a material override default middle gray. Start from scratch with the defaults.

Start with your GI. Dont add any lights, just get the sun and sky illuminating the scene correctly and your render nice and smooth, then go from there.

 

 

Are you doing an animation or still?

 

What machine are you working on (RAM and Processor)?

[MasterZap]

i know this is a complete and utter noob question, but i am totally loosing it with lighting for interior scenes using mentalray. ARTIFACTS EVERYWHERE, i have done all the usual stuff like deleted/recalculated the fg numerous times on numerous files. i have gone into a total flatspin because i cannot get it to work and i have since tried to add and remove speckle reduction with no effect, removed and added various lighting systems, tried it with and without global illumination and and and and...... i'm loosing it, help would be appreciated. using mr photo exp fyi, SKYPORTAL A HOAX!

 

It doesn't seem like you are using the sky portals at all - the image sure doesn't look like it. Did you place them exactly in the windows, pointing in the right direction?

 

/Z

[AJLynn]

There's some stuff in there that's inexplicable - are there geometry issues in the ceiling? It doesn't look much like anything I've seen mr do. BTW when properly used the light portals do considerably increase FG performance.

[xeunox]

i try to stick to arch design materials and basic materials for simple colours, anything that has a bump or specular or transparency is usually a arch design material, simply cause it's very easy to use. i tend to stay away from lots of reflections just to optimise renders.

 

As for lights, in this specific render i used a couple of photometric area lights, and the mr sky/sun setup, those are the only lights i've used. i did have sky portals exactly in my windows yes as masterzap suggested, and all the correct flux directions where set, but i took them out of the scene because they created a massive light streak on my floor where there should be shadow (???) (i just vented, my bad)

 

 

Tommy these are still renders only, no animation, i was hoping to do a vr later but qtime full of issues on my 32 bit machine. I have 2 machines, main: mac pro 2.66 dual quad, 8 gig ram, standard 7300 nvidia, running vista 64, no problems, other is a AMD4000+ xp machine, with 2 gigs ram, 7600gt nvidia(don't render on this one), i will do that material overide and try again, (render the fg/gi out with that rather than textured? and apply once rendering with textures?)

 

thank you for your responses so far.

[xeunox]

hey andrew, yea there are supposed to be lights there, lights which i have tripple checked, models that i built myself, simple light box, no funny settings on geometry settings, no transparency no nothing, simple 12 poly boxed lights, with standard materials, not arch design, using a grey exterior, and a white self luminated interior. thats it. this is what it does to my poor ceiling...

 

i swear this is the weirdest experience i've had in max since i started 7 years ago...

[Tommy L]

 

(render the fg/gi out with that rather than textured? and apply once rendering with textures?)

 

thank you for your responses so far.

 

No, I meant you need to go back to basics with the lighting until the lighting problems are resolved. When you have a messy result like this its best to know whether it is caused by bad lighting or modeling or render settings. If you have jut one generic material, it rules out any material errors causing weird problems.

 

I agree with who ever said you have geometry problems in the ceiling.

[AJLynn]

Could you elaborate on that boxed light setup? Where is it? are you talking about a rectangular box around the entire scene with a self illuminating interior surface providing you primary light source? I don't think mental ray would be happy with that sort of thing.

 

Try one where you have the light portals in the windows (arrow points in) and there is no geometry surrounding the scene and no lights except an mr sun and mr sky, FG is turned on and you use mental ray exposure control (the indoor sunlight preset is a starting point). The window glass should be Arch&Design thin geometry glass, which will be dealt with correctly by the renderer. To keep things simple use a matte light gray A&D material for everything else in the scene and see if you can get the lighting to work.

[xeunox]

Thank you guys, its looking a lot better

 

Here is a new render with the settings i have used.(changes marked in red)

 

Just a quick question, what does the "from outside" switch do on skyportal?

 

Its still looking very grainy, when i up the shadow samples on the skyportal from 16 to 64 (also deleted/recalc both fg and gi on same settings) this is what i get.(image 2)

[Tommy Burns]

A couple of things I've noticed have only done a few int renderings with mr but I always got good lighting. First I would say is I always use FG at Draft standard setting maybe Low but never medium must take ages to render.

Not to sure on this but you have Read/Write and Read only ticked. I would usually do a test render with none of these ticked so I am getting no saved settings in FG.(I think this is your main problem) Then if it's right I would use the read write option to speed up the main render. Also I would use photon radius this seems to help. I change physical scale to Unitless and enter 90,000 and use a preset in PH.exposure control. Could be a bit off on some of these but I nearly always get great results with these settings. Let us know how you get on?

[xeunox]

This is where i'm at now, still having problems with grain. suggestions welcome

[xeunox]

hey thomas, thanks for your input. Most of my work i do for print, and i need to render out a4 300 dpi tiffs, what i do is calculate the FG on a a4, but at 72 dpi, while saving the fg file, i have a dual quad core system, medium settings doesn't take to long, about 5 minutes for this specific image. After this is done, i up the dpi and lock the fg, its works well. If i use draft quality, its gives me artifact, not always though. Is this wrong?

 

while i'm on the subject of rendering, i want to know how you guys render out your more complex scenes, with lot of geometry it gets difficult to navigate through the scene, and takes even longer to render. I know putting everything at once is the wrong way to do this, however, when one hides layered/grouped geometry it gets excluded form all sorts of light/shadow calculations. Compositing after in photoshop is easy, but it never looks right. I use a global material override with a ambient occlusion MR material, on everything, as a final layer on multiply setting. maybe someone can give me a better solution.

[Tommy Burns]

Hi pieter

Not too sure what you are doing with the dpi thing never use this workflow. If I get artifacts usually it is something to do with photon settings not high enough or too high. Using the photon target radius seems to help although some scenes I don't even use photons (Trial and error).

As far as rendering out your scene Jeff Patton has a post in here about "subset of scene" it is a hidden shader and it does all you want for compositing it's brilliant and easy to use. You can probably find the tutorial on his web page.

Keep us posted how your getting on?

[xeunox]

fyi tommy, DPI (dots per inch) has to do with the amount of pixels in a square inch, large print quality is usually 300dpi, newspaper 150dpi and your screen has a resolution of 72dpi.

 

A standard A4 paper real world size is 297x210mm.

 

a4 high quality render @ 300dpi is 3504x2479

 

i use the print size wizard under the render toolset.

[Tommy Burns]

Cheers Pieter!

 

Just had a look at this and it's a handy tool I always just used the render scene dialog. I don't understand what this has to do with FG and saving an FG file. I think you can save a smaller FG sometimes and then print at a larger resolution but i never do that I always create the FG file at the size I'm printing and if it's right I save it and use read only for speed of render. Don't know what's right here maybe someone else might clarify.

[xeunox]

try calculating fg on draft, on a a4 of 72dpi, and then on 300dpi, using a semi complex to complex scene and you'll see why. i do it for render speed, but also so keep the correct size of the fg solution on a larger scale with very little change in quality

[Tommy Burns]

I understand that Pieter but maybe this is where it is going wrong for you?

Cheers

[xeunox]

subset of scene shader, i've looked in the render dialog in the lens shader slot, but i can't find it there, also can't find the topic on jeff's blog.

[Tommy Burns]

subset of scene shader, i've looked in the render dialog in the lens shader slot, but i can't find it there, also can't find the topic on jeff's blog.

 

This is the tuorial here http://www.vizdepot.com/forums/showpost.php?p=57290&postcount=8

 

But first

 

You also have to unlock the proceural shader (subset of scene) in your ini file it is a hidden shader have a look here. http://www.lysator.liu.se/~zap/pd/unhide-max.html

 

It is well worth doing this there are lost of hidden shaders but this ones a gem

Enjoy!!

[xeunox]

final camera 1

[xeunox]

here we go again, cam 2.... delete both fg and gi calcs, changed the exposure to compensate for light changes, and recalculated the fg again, and its artifacting like the 1st image again...

 

i have now switched of both fg and gi and i'm just using the exposure controll to render out the image, its looking ok, but it has to do, cause my time is up... i will post as soon as it finishes

[xeunox]

ok well this makes no scence, i tried something, i moved the camera i used in scene 1, onto the position of cam 2, recalculated the fg, and its perfect?!?!?!?

[Tommy Burns]

Well delete camera 2 and animate camera 1 for all your scenes and images:)