Hi anyone. I do quite a few visuals using photometric light using webs. However I have noticed that if I use a spotlight and set the falloff field beam 120 degrees then I end up with black ceilings i.e. they receive no light. If I then only change this angle to say 110 degrees, the ceiling is illuminated perfectly.

How strange - does anyone know if there is a reason or fix as sometimes I want more than the 120 degree. ?

Any comments welcomed.

Ta

Can you post a scene that shows the problem - I can’t reproduce it here.  I really don’t know the internal workings of photometric lights, but could it be you’ve just found a sweet spot where intensity divided by falloff distribution is not enough to make it back to the ceiling?  Are you using an exposure control?

MP

Max 2009, 2010 32/64
VistaP 64 SP1
Intel Q9550 8GB
ATI 4870x2
Patriot 128GB SSD

Thanks for answering.

Attached is a ZIP of the Max file with a few JPGs that are used. I have not used photometric IES lights in this one - just photometric spotlights. Originally I had 60deg beam and 120deg fall off and the whole ceiling was black. With the fall off at 110 deg the ceiling is illuminated OK. The file attached is saved at 110 deg.

The central light fitting has a simple uplight to illuminate the ceiling also.

I normally do specify lumens for photometric lights and actually I like the logarithmic exposure control instead of the MR exposure control.

Anyway if you do take a look I’d be interested to see if it happens on your MAX.

PS the JPG called meet4ing4.jpg is the final render.  Not perfect - it was done as a quick favour for someone of a meeting room but looks OK.

Cheerio

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19299_4vmU8BUU2HOIJ8nSLvFh.zip

First thing I noticed was the frozen FG map. That could be the problem. Rendering with 110/120 falloff produced the correct results, definitely no black ceilings.

Couple of side notes:
- Be kind to your fellow testers: Make your scene as light as possible and with draft settings / resolution. The first thing I do is hit render, and when my computer chokes, my eyes get a little watery, and I might let out a little whimper.

-Noise Reduction is not as needed in a scene with relatively consistent lighting
-EDIT: Correction

-Modeling with planes as walls can lead to all sorts of lighting (leak) problems - and probably doesn’t help in scene optimization.

-Open the mentalRay message window while in testing - lots of good info there, as well as warnings.

That’s it for now, let me know if the frozen FG did the trick.

MP

Max 2009, 2010 32/64
VistaP 64 SP1
Intel Q9550 8GB
ATI 4870x2
Patriot 128GB SSD

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Thanks for your help MP.

I only left the settings as they were so that you could see it exactly as I had it. Hope your cancel button worked OK.

The FG map was frozen because I do FG with a small resolution first i.e. 512x389. Then when I do a full render I lock the FG map and set the render res to say 2048x1556. If I do an FG at the full res it takes ages (which is why you commented about the ‘being kind bit’). I was taught this by an AutoCAD Max training technique.

On the noise, I use the noise filtering as it is in the FG section and its not in the GI section. So Im not understanding why I shouldnt use it - but will try a test as you seem to find it OK.

If I find the problem again I’ll come back but for now really appreciate your time - so thanks

I only left the settings as they were so that you could see it exactly as I had it. Hope your cancel button worked OK.

Hehe, yes cancel works fine, I meant that only the room and the lights needed to be in the scene, the plant (for example) was not affecting the lighting solution.

The FG map was frozen because I do FG with a small resolution first i.e. 512x389

That’s fine, and a practical way to approach it, but if you make any changes to your lighting, it invalidates the FG solution. That doesn’t mean it throws an error, it just means any information from the FG map is old / not valid for the change in lighting. Changing from 110 to 120 falloff, without updating the FG is what I’m talking about.

On the noise, I use the noise filtering as it is in the FG section and its not in the GI section

I revised my earlier post to better describe it. (The help file explains it perfectly), but for convince I’ll pose it like this; the less light (or light sources) in your scene, the more you (could) use noise reduction. With a well lit room (as is yours) there is not much need for any reduction.

Good luck,
MP

Max 2009, 2010 32/64
VistaP 64 SP1
Intel Q9550 8GB
ATI 4870x2
Patriot 128GB SSD