Black Artifacts when using Final Gather Map

[THEPRAYINGMANTIS]

Hi All,

 

I normally use Vray but this particular job I decided to try Mental Ray Sun and Sky. Its a large image (Billboard size) and so I'm using a saved Final Gather Map for the final render. Unfortunately I'm getting black holes, basically areas that are missed. My renders are looking like swiss cheese. What am I doing wrong?

[illegalalieninbeijing]

Unless you have a more powerful computer with lots of ram power, I suggest you lower your FG sample. If you are using Viz 2008/3ds Max 2008 they have presets for that. A "low" setting or about 200 FG samples would eliminate that ( I hope ). Lower your Noise filtering (speckle reduction ) to "standard" will also help.

 

If I'm showing a bit of a close up and want it to be crisp and clear I would increase all of those settings above. But I will render it by segments using regions. I usually do this if I use a much slower computer.

 

I hope that helps.

[Justin Hunt]

The black hole are caused by the frame buffer running out of memory, things to try

 

1) generate your FG/photons at half the image resolution, freeze and rerender at full res. This is a good practice regardless of black buckets or not

 

2) Turn off the frame buffer

 

3) render through backburner

 

4) Play with the BSP settings

 

5) Use mrProxies (maxdesign2009 only)

 

6) optimise your FG/ Photon settings to be more efficient. Often the presets can be too high, start at Draft then Low, medium and High can be killers

 

jhv

[shaneis]

Adding to the following point,

 

...Are you rendering to an optimal resolution? I have seen some guys calculate billboard render resolutions by using a 300 dpi setting, which is waaayyy overkill for something of that size...

 

Here is a link to help you with your DPI, note that they mention a 14' x 48' bilboard typically uses between 2 to 20 DPI.

 

http://www.signindustry.com/outdoor/articles/2001-03-19-viewingDistance.php3

 

Hope this helps,

 

S.

 

Edit: And another one with a bit more info...

http://www.graphic-design.com/Photoshop/Tips/9807/109.html

Edited June 26, 2008 by shaneis

[THEPRAYINGMANTIS]

Hi all,

 

Actually I have an even bigger problem. I'm using RPC'S in my scene and I'm getting error messages. They are rendering out as solid red but some are rendering out fine. I know there's a plugin to resolve this. But why are some okay and some not? Is there an easy fix?

[illegalalieninbeijing]

Are your RPCs in the foreground? If hardware is the problem, try rendering the RPCs seperately with an alpha channel. Cut and attach them in photoshop. Shadows can be daunting - you have to add them manually.

[illegalalieninbeijing]

The black hole are caused by the frame buffer running out of memory, things to try

 

1) generate your FG/photons at half the image resolution, freeze and rerender at full res. This is a good practice regardless of black buckets or not

 

2) Turn off the frame buffer

 

3) render through backburner

 

4) Play with the BSP settings

 

5) Use mrProxies (maxdesign2009 only)

 

6) optimise your FG/ Photon settings to be more efficient. Often the presets can be too high, start at Draft then Low, medium and High can be killers

 

jhv

 

In addition to what Justin Hunt said:

 

1. Upgrade to a quadcore processor, increase ram capacity and upgrade to a 64 bit version of 3DS Max.
   
2. Make a habit to reboot your computer before doing a new render.
   
3. Close all other application/programs running in the background ( anti-virus, internet, etc.)
   
4. Turn off the rendered frame window ( a.k.a. the frame buffer )
   
5. In sampling quality/samples per pixel: use smaller bucket size. In filter: start with box for test renders and mitchell for final renders.
   
   

6. Do a netrender

   
   

[Justin Hunt]

The RPC issue is due to the RPC not being loaded at rendertime. This could be down to a network error or simple the plugin falling over itself. Happens often.

 

Most of the time a re-render solves the problem.

Or a restart Max

or store the RPC on the local machine

Make sure the content manager is properly configured and sees all the RPC's including any in sub-folders

 

jhv