Urgent problem in ArchViz (mr)

[mortin]

Hello!

 

Firstly as a new user I would like to say hello to everyone and thanks for great job that you do by developing that forum.

 

Secondly, I decided to post my problem here because Im quite desperate with that design. To introduce you to problem issue Ill say that I have to finish vizualisation of my design till Wednesday to pass one of the most important subjects on my studies (faculty of Architecture). But I cannot solve the problem of interesting light and rendering time of my scene.

 

The idea in this this design was to create some kind glass casquette of light hidden inside slashed, concrete cube. I've already modelled the interior and applied some materials but the trouble begins with the light and the size of the render. The final picture will be put on the board 100x70cm so it has to be at last format A4 (3508x2480 px). When I put 3 lights into the scene ->Daylight system and mr Sky Portal the render cant even finish up the photon emission.

 

I have no idea how to optimize my scene and the deadline is coming. The whole scene has 3,5 mb. Maybe someone will be generous and can help me to find a solution for that problem I can even pay for that:)

 

I have to find a compromise between realism and the render time.

I work with Mr in 3ds Max. My system specc: C2D 7500, Radeon 2600 HD, 2 GB RAM.

 

Unfortunatly I cannot post a link to the sample low quality render:/

 

Im looking forward any tips and your replies.

 

Please help me guys and sorry for my english but i havent sleep for last 30 hours.

[neko]

i've only got a couple of minutes, but have you tried rendering using the MR rendering presets at the bottom of the render dialogue ?

 

i can't remember all the preset names, but there are a few for daylighting interiors low-res (for a starter).

 

hope that helps (a little)....

 

best of luck

[mortin]

Thank for a advice. Ill try it after test render with higher sampling values will finish. I have to take realism into accoun too of course:)

 

Greetings, I hope I'll solve it soon.

[TheAllusionisst]

You might start by calculating and saving GI/FG at 25% resolution and then lock/freeze the solution and use it when rendering the full resolution version. That should help on memory. As for quality I would leave the other settings default and tweak the anti-aliasing for quality. Sampling next...... Other items are shut everything else off (other programs), set view ports to bounding box, smaller render buckets, tune BSP or use BSP2 and turn off scanline.....

 

There are many places with good tutorials on mental ray, you just have to look, I personally think Jeff Patton does a great job you should read his Blogs here:

 

http://www.mrmaterials.com/ and Master Zap has a blog http://mentalraytips.blogspot.com/ and Brian Bradley's http://www.mentalboutmax.co.uk/ and there is a long shader discussion at CGS http://forums.cgsociety.org/showthread.php?f=183&t=104578&highlight=mental+ray+shaders

 

Good luck!

[alff]

Hi Morcin,

 

can you post either a low quality image - or- if this is not possible - an image of the 3dsmax viewport so one can see where

- the camera is

- where your lights are

- where the concrete parts are

- where the glass is, and how it looks like (shape)

 

Without this there can be 1000 reasons, and you dont have time for that.

 

Why do you need photons at all ? Do you want/need caustics ?

Do your objects have ´caustic receive´flag set ?

In mental ray you can flag all objects to generate or to receive caustics.

This can be used to accelerate things. Typically you could set the glass objects to generate caustics, and then only the final floor/concrete to receive caustics.

How many photons do you try to shoot ?

 

What is your photon trace depth ? To run through glass it needs to be higher. Like if you have 10 layers of glass this is 10 time 'in' and 10 times out so you would need photon trace depth 20.

But do you really need caustics ? Maybe you can switch them off and gain speed that way ?.

 

 

If you dont need caustics you can use final gather only. That might be faster (depending on how your scene looks like, so please post an image, even if it is just the viewport with smooth shading or wireframe).

[mortin]

Thanks to yours advices Ive finished interior renders Ill post them soon but I have problem with the exterior lightning at night. I have daylight system set at 23hr and whenever I add any omni or target to imitate interior lightning it doesnt take any affect. What can be the cause of that situation?Any ideas?

[SandmanNinja]

That's because light bulbs don't come close to putting out the same amount of light as the sun or moon.

 

I have found that I need to make some lamps be non-photorealistic in a photorealistic scene. So:

750-1000 candelas seems right for a bedside lamp.

1500-3000 candelas seems right for a corner floor lamp.

[mortin]

Yes I got it but it doesnt take any effect even if I deleted the daylight sys.

[alff]

Yes I got it but it doesnt take any effect even if I deleted the daylight sys.

 

 

Hi Mortin,

 

i am not sure what you exactly do when you say you use a 'daylight'.

 

1) do you use mental ray as renderer ?

 

2) if yes - when you create a daylight system - did you switch the sun to 'mrsun' and the sky 'mrsky' ? These 2 are the better working sun and sky.

 

3) What aboud the tonemapper / exposure control

 

a) is it active at all ?

b) if one is active - which one ? mr photographic exposure ?

 

If you are not sure - check Rendering->Environment->Exposure Control. Switch to 'mr Photographic Exposure Control" if this isnt on yet.

Then set "Exposure Value (EV)" to 6.0. I just tried with a daylignt system at 23 hours (= deep night). This works fine (i was surprised to see a background sky, but anyway it worked).

 

 

4) When you add a light - Max has 2 types 'standard' and 'photometric'.

make sure you use 'photometric'. Try or example "Free light". When you start the light choose the template 'select a light' (at the top of the dialog) and select for example "75W Bulb". Also make sure to switch on shadows and 'raytraced shadows'.

 

In my quick test this works like a charm and i can see a bright light.

Dimensions of my model are small however - 40 cm cube on a 200 * 300 cm plate. My light is close to the cube.

 

When you use photometric lights your units must be correct. A 75 Watt light would be black when you put it in a football stadion (200 meters wide). The same light is bright in a small room.

[mortin]

Thank you very much. The reason was the light's intesity:) Ill post some effects soon. cheers