Studio Lighting.

[rajdarge]

I am trying to simulate in 3ds max the lighting I have in my photo studio.

I have many lights and modifiers and am trying to duplicate those for use in photmatch.

I can simulate a softbox with a square vray light.
I can simulate an Octobox with a octagonal shaped poly made into a mesh light.

I can simulate a strobe with a snoot, but it seems ineffecient modelling a snoot.

I cannot seem to accurately simulate a speedlight (small camera flash)
I cannot seem to duplicate a spot light, Either with or without lens.

I cannot even concieve of how to duplicate a softbox with a grid.
How to duplicate the look of an shoot-through umbrella escapes me.

The other problem I run into is setting the power of the lights. Studio Lights are determined by their Ws or Joule amount. 180-400-600-1000-1600 are common numbers. But how do I convert them for use into 3ds max?
(the numbers are not arbitrary but many manufacturers play around with the numbers to sell their product).
I have not found IES data for any of my studio strobes.

This work is to provide new backgrounds (and foregrounds) in 3d for my portraits.
If anyone is even slightly interested here is my work:
http://www.pbase.com/refinedreflections/galleries
Here is an example image:

(there is some nudity but its tasteful).
I work in Hi-res (5000x3000px) and Print to a large printer (A1 size).

So the effects have to be accurate. I have been casting an artistic eye and "winging it" so far, but I was wondering is there a better, more logical way?
This is an example of a previous attempt that failed:

Raj

[JeffG2]

You're looking for something like this: http://www.luxology.com/store/SLIK/ for Vray.

Me too!

I think the Chaos Group is missing out on significant sales by not providing something like this - for those of us who don't have time to reinvent the wheel.

[rajdarge]

Much of the SLIK kit is modelling the various lighting modifiers. I can model all of that stuff already. If I want it to appear in my shot, I just take a picture of it. However it was the efficient and accurate reproduction of the Quality of the light that I want as the modelled components will not actually appear anywhere.
The fresnel spots pictured are interesting and I think I would need a IES editor to make them.
If modelling the egg-crate grid for the softbox is an accurate and efficient way of reproducing the light from a real world example - well consider job done.

WHat i also need is a way of converting the power of the lights to more accurately represent what I see in my studio.

I hope that makes sense.
Raj

[raymarcher]

You're looking for something like this: http://www.luxology.com/store/SLIK/ for Vray.

Me too!

I think the Chaos Group is missing out on significant sales by not providing something like this - for those of us who don't have time to reinvent the wheel.

So true, this is for many people a show stopper.

[Preisler]

Total agree! This post should be in the wish list

[rajdarge]

ideally I would also like lights intensity to be modulated in stops, I would also love a light meter that read things in stops and shutter speeds. I guess with 32 bit imaging a light meter is kinda useless, however unless I spend an age compressing my images colour range, I usually work in that 8 bit sweetspot and try and expose everything to be in that area. All the rest gets thrown out when I go to print.

I'm not sure if the SLIK thing does really what I'm asking for. Looking at this image:

what do I need all the detail of the modelling around the light, if all I'm interested in is the effect that the light produces.
Take a look at the detail here:


All I want is the effect, not the full modelled studio kit.

So I believe that kit is mostly designed for those that want to DISPLAY a studio environment with studio equipment in the final image.

But thanks guys I'll have to try and work out a way myself. Maybe lele can help - does he still come here?
I'll post anything I discover here.


It's a shame that it has to be added to a wishlist: I would have thought that it would be a no brainer and therefore someone had done it before.

Its also a shame because I have a client who wanted these images on Monday (its now thursday 4 days over due).
Bummer.

[tammo]

What about taking a HDR photo from the front of the real light and map that image on a square vray light?
We could build an image Library of different lights and name them with the shape and brightness value and share them.

[rajdarge]

Problem with this approach is standardisation. Different cameras lenses, distances etc. ALso HDR images aren't standardised for light - they just describe relative light amounts - there are no absolute measurements.
I could shoot a HDR probe of my studio setup at the point where the subject sits, however every time I move the light, or the subject I would need to re-shoot. ALso I sometimes set up lights in max first and reproduce them in my studio.
I can measure the lux output at a particular point with my light/flash meter. Is this useful.
What we need is someone with a deep technical knowledge of the way vray simulates lights and how to apply that to real-world examples.

[glorybound]

is this script useful?

http://www.scriptspot.com/3ds-max/sc...udio-setup-pro

[stef.thomas]

Or how about this? HDR Light Studio

[rajdarge]

wow, expensive. Could be what I'm looking for, though its very brief on detail. It doesnt actually tell you much about the softboxes that it can create, it might do no more than what you can type in to the modelling panel. Plus is it calibrated to give real world numbers.
Interesting concept though

[rajdarge]

HDR light studio is best if you have primarily a CGI subject. I have live subjects (usually, though they may appear dead). I suppose I could light my 3d scenes with a light probe till I can figure out a way of calibrating Vray lights.
Plus to a tog like myself it seems counter intuitive to use a 2d space to set up lighting when I have a 3d editor (3ds max) to set up lighting just like I have in my studio.
If anyone wants the light probes, I'm happy to give them away - studio lighting is a closely guarded secret till you read your first book on the subject. you then realise that everybody knows it except you.

[JeffG2]

There's more info on SILK here: http://www.koudis.com/blog/daylights/index.html
and here: http://vimeo.com/9276370
and here: http://vimeo.com/9297522

Might be of some use in this process of setting up a Vray version.

[rajdarge]

I have watched the videos. Even if I had modo, it wouldn't satisfy my needs. If someone (us?) were to create a similar product for vray I would want it to be substantially different.
The heart of the SLIK system is a single IES light that is modified by the various modelled light modifiers to produce the intended light effect.
This is good, but I would suggest extremely inefficient. It uses a SSS material to simulate the effect of the softbox. I would have thought that would be the SLOWEST method to produce a softbox effect? More efficient would be a simple square Vray light with perhaps a gradient ramp mapped onto the light to regulate falloff. Why involve all that extra computing needed to first bounce off the sides of the softbox then diffuse through the SSS material and then hit your subject. Thank god they don't have an internal diffuser inside the softbox as well (as most sofboxes do). Rather than rationalise use of geometry they have just reproduced it- verbatim. They have even modelled a modelling light - of what use is that?
So someone find that IES light and I could create the functionality of that entire system in perhaps a week. Maybe not the detailed geometry but its effect on the objects rendered.

But the root problem is that they use w/m2 for their light intensity (also in vray) but I use Joules in my studio. Furthermore I then work in stops . My 2 main Elinchrom lights go from in a range of 6 stops for their intensity from 2-8 in 0.1 stop increments. Colour is determined in Kelvin even for gels and reflectors. Rosco has done all the hard work there.
The vray physcam is better than theirs. The Vray lights are better than theirs.
So I think it's time that someone with a lot of technical expertise with vray answer the question: is to model all of that geometry and use SSS for lighting a secondary object an INEFFICIENT simulation or not. I think I know the answer to that question already.
So let me ask the other users who are interested in this thread: are you really wanting all that geometry or are you just interested in the lighting effect (as I am)?

By the way I've figured out how to do the shoothrough umbrella and the reflected one is a synch. To model a 15degree grid would be extremely geometry intensive and perhaps inefficient. Can someone think of a better way of simulating a grid?

[rajdarge]

Ok just doing some experimenting.
I made a flash tube sized flash 35mmx70mm (approx) and put a box around it and flipped the normal and knocked out the end bits. . I didn't put a diffuser panel, just the equivalent of a snoot.
Hit render and the thing I noticed most was the amount of grain introduced with the snoot.

The lighting looked real world and certainly using a power of 60w in radiant power mode I got a decent exposure, like i'd expect. Even the shadow was realistic. But there was a lot of artefact and a lot of grain on the vray sphere that was my subject. this dissapeared when I ticked "store with irradiance map" on the vray light.
So if that is the amount of artefact that I got, with this method ( without storing it in the irradiance map or making a hDRI probe) the amount of noise would be worse with a grid across a larger rectangular vray light.