View Full Version : photon map fast inaccurate effect script

09 September 2003, 10:14 AM
Good morning ppl!

I've seen an article lately (last month) about how to fake a photon map, or is it called radiosity? i'm sorry to be confused by those terms abit... I mean when light passed through a light and get focused in a spot. (Well, if you are here, what are the differences exactly? Is the radiosity the effect, and photon mapping the technology?)

Anyway, It says, high everything, but your glass-object, give it a falloff map - for the opacity, and a good specular. render it from the light point of view in a size like 1000x1000 (1x1 i mean). Take it to photoshop an by gradient+quick mask and by gaussion blur, blur it more and more as it goes upword (to the far distances between the object and its surroundings). Then use it as a shadw map for the light, duplicate that light and use it not as a shadow, but as a projection map.

I had a better idea of taking the read channel in photoshop and skew it a bit to the right, and the blue one - skew to the left side - for having a rainbow.

I know that effect is far from being realistic, but it's quite cool and it looks good!

It seems as an easy maxscript writing (i'm not so good in it, i'm only a beginner in scripting - for every command i have to look in the help for hours - not very practical yet) - becasue the logic behind it is very simple and very linear procedurally... In a matter of fact, it's only a macro, not really a script... record an order of commands...

Anyway, it can be cool to add parameters like:

- how much to skew the channels to have an extremely rainbow?
- how much to blur (DOF)?
- specular and falloff controls.

Well can anyone do/have such a script or atleast help me where to find all the help i need, becasue i'm not sure how to do a 2d processing with maxscript if possible... well, i have never used the material scripts yet... mmm... it's not so easy when you don't know the commands very well... :hmm:

09 September 2003, 10:38 AM
OK, It seems as if i wished a way too big ask, So I'll start with a smaller question:

Does anyone know how can i do those 2d manipulation with maxscript? (i guess i can't, but i have to confirm).

09 September 2003, 12:01 PM
I don't really understand the post about fake photon mapping, but for manipulators, simply lookup the word manipulator in the maxscript online reference.


09 September 2003, 02:10 PM
I didn't see anything in the maxscript (but in a fast glance though...) - I'm talking about picture manipulations, not manipulators aka blurring, skewing RGB channels...

Anyway, I'm talking about caustic. It's strange, one moment i can't recall the word, another moment i can't understand how i was so confused... :blush:

Here's an example from final render's site (i hope it's ok posting it here...)

If you look from the light point of view, You'll see the specular highlight in the middle of the sphere. If you use that picture as your shadow map - you'll have that highlight in the middle of the shadow, and by that you create a fake caustic. But it has to shine more then just not having a shadow there. Therefore you should make a copy of that light, but instead of a shadow mapping, use a projection map, so it will project bright spot in the middle of the shadow (ofcourse you have to make that light exclude the lighten object - sphere in that example).

Anyway it's not accurate, but it gives nice results and it's much more faster!

10 October 2003, 01:04 PM
i see what you mean, and wish you the best luck getting it done, i've looked into maxscripting a bit myself but i suck, and have to concentrate on other things ATM, however, a decent work flow occurred to me, have the script ask for which light is casting the caustic, ( so it knows which one to copy) have it copy the light and shrink its hotspot and falloff cone by atleast 50%, increase its brightness by a variable amount, i'd say starting with 3 times the current, then ask which object is creating the caustic so it can exclude it from the shadow casting, all easy to say i know but hopefully it will all help, however remember you'll only be able to do simple single hotspot caustics, because anything larger has to have a convincing pattern and that is pretty hard to fake, ( a lot of those patterns are really weird, but you're eyes can spot a fake a mile away)

10 October 2003, 02:27 PM
hehe, it took a month for a reply :) 10x anyway!

Well, 1st i thought to put the ui of the script as a shadow plugin - that tells the 3dmax what's light were talking about.

Anyway, I have so much other things to do/learn so i don't see myself doing that script. I started once learning 3dmax's script. I did some very short scripts... It's a problem when u don't know the language and max's debugger sucks.

Well, If there's anyone there who wants to try, tell me! i'll be glad to be a beta tester! (yeh! take the easy job, right...) ;)

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