IRRADIANCE MAP SETTINGS FOR PARTICULAR RESOLUTION

[oncire]

What is the setting of min & max rate of irradiance map for particular resolution?
say for 1024 X 768? or 3300 x 2550?
-is it the same setting use in lower resolution when rendering in larger resolution?
-or can you lower the min & max settings when rendering larger resolution to get faster results but maintaining quality?

[dalomar_cg]

Re: IRRADIANCE MAP SETTINGS FOR PARTICULAR RESOLUTION

It is no where near the same settings, so don't go with the regular settings, or you'll be waiting for hours.

IR is actually "meant" to act correctly at screen resolutions, so about 800x600. Whenever you go beyond that resolution, you should make sure that your IR min/max rates reference the screen resolution as opposed to final resolution. The easiest way to do this is to simply render out your IR map at a screen resolution (but with the correct aspect ratio of course), save it, load it (change IR mode to from file), and then change to your final resolution. This will make sure that you are always using the min/max rates effectively.

The second way to do it, is to set up your min/max rate for a lower resolution. And then keep track of how many times your resolution doubles. The number of times it doubles will be the factor that you need to decrease the min/max rate. The only problem with the doubling method is that many times, the final resolution isn't a simple product of doubling. That means that you'll have to pick a side to lean on. A quick example below.

@800x600
min/max = -4/1

@1600x1200 (doubled once)
min/max = -5/-2

@3200x2400 (double twice)
min/max = -6/-3

@6400x4800 (double 3 times)
min/max = -7/-4

You'll notice that between our base resolution, and the last example the min rate of the screen res effectively becomes the max rate at hires. That means that if you didn't change the min/max rate, then you'd be starting your IR calcs at final quality, then proceeding to psycho-uber quality. Of course this will take a lot of time, but the other side effect is that the IR map becomes astronomically huge (I've seen upwards of 500mb for incorrect min/max rates). This take a whole lot of memory, and may cause crashes that are unnecessary.

[oncire]

Re: IRRADIANCE MAP SETTINGS FOR PARTICULAR RESOLUTION

thanks for your reply. i think i prefer your first suggestion...honestly i still dont know how min & max rate works.. so i'll just stick to your first suggestion.
- i have a question should i "always render my image to 800 X 600 resolution"? then when i want to render my image at higher resolution,save & load the ir map the set my desired higher resoution.(say 3300 X 2550 or something 4000 X 3000)
to simplify (is it always 800 x 600 for the base image?)

[dalomar_cg]

Re: IRRADIANCE MAP SETTINGS FOR PARTICULAR RESOLUTION

800x600 is just a guideline, so use whatever is the aspect ratio that you're looking for (4:3 or 1.33 is common...most widescreen monitors are 1.6) and set that up for screen resolution (so 1024 max in one direction, 500-600 minimum in either direction). As long as the IR map is calculated at the same aspect ratio, then you'll be fine.

As far as what min/max rate is, its actually describing the different resolutions that the IR map is calculated at. So a rate of 0 means that the calculation will be done at the same resolution as the final image (for the following examples, lets say 800x600). A negative rate will decrease the resolution by half with each step (so -1 would be 400x300, -2 would be 200x150). A positive rate will calculate beyond the target resolution (so 1 will be 1600x1200, and 2 would be 3200x2400). The difference between min rate and max rate will determine the number of prepasses, or the number of different resolutions that are sampled. It will also determine the amount of adaptiveness of the IR solution. Thats about as quick as I can go over it.

[oncire]

Re: IRRADIANCE MAP SETTINGS FOR PARTICULAR RESOLUTION

Thanks for your time replying to my querries.keep up the good work..I think i know now somehow what you mean with the base image.as long as i know the aspect ratio then i should keep also the aspect ratio of my final hires image.