Friday, 13 July 2007

HDRI GI Composition Mini Tutorial

This is a brilliant tutorial based on a scene my good mate -R3D- gave me, so all credit goes to him for the scene, but here's a tutorial on the basis of this setup. Now this is a mini tutorial for Cinema 4D, however you should be able to get the same effects with using other software, as i've not got any other software I cannot be sure. So apologies if this does not translate perfectly.
Building Up The scene
Grab yourself a camera. Set it's projection to perspective, with a focal length of 36, an aperture width of 36, set you field of view to 53.13* (* Indicates Degrees). a film offset or X & Y of 0%, enable near clipping, and show camera cone.Set your camera coordinates as the following, positions X = 600m Y = 300m Z = -600m. Sizes X = 1 Y = 1 Z = 1 and the rotations as H = 45.3* P = -15* B = 0*.
Protect this camera, you won't want to move this camera, if you wish to have a different view of the HDRI, just rotate the HDRI itself.
Setting Up The Environment
We'll be needing to divide the environment into to environment, a visible environment and your GI environment, and of course a floor.
The Visible Environment
Start by creating a new primitive sphere, and give it a radius of 6000m with 24 segments. You'll also need to create a compositing tag, you'll need everything ticked apart from the compositing background & GI, this a visible environment which means this will act as your reflections on your objects and nothing else.
GI Environment
Repeat the same steps as before, create a primitive sphere with a radius of 6000m and 24 segments, and again add a compositing tag, this time only enable casting shadows, shadows received, self shadowing, seen by transparency and of course seen by GI, you won't need this to be seen by a compositing background, the camera or rays.
So we'll be using the same HDRI for both the GI and the visible environments, so that the lighting and the reflections are created the same. With luck that'll mean that your object(s) will appear as if they are actually within that scene.
Setting Up The HDRI
Ok, so now grab your HDRI, you'll need a pretty good one for good enough detailing. I'm using a HDRI known as City Center which is 3000 x 1500 RGB 32 Bit HDRI, this is very high resolution and perfect for what we are trying to acheive.
We'll start setting up the GI Environment HDRI first, swtich on your luminance channel in a new material, create a filter layer and load your HDRI into the texture section. I've correction the gamma on the HDRI to a setting of 1, it's more realistic that way, anything higher will be saturated. now add the following settings with the filter a Hue of 0* Saturation of -100% Lightness of 0% don't colourize and leave a brightness & contrast of 0%. Also give this HDRI a blur scale of -40% too.
For the visible environment just load the HDRI into the lumianance channel of a new material, and again give it a -40% blur scale.
Lastly we'll need of course a floor. So go ahead a create a normal floor and create a new material and place a HDRI into the colour channel this time and again a blue scale of -40%. and a brightness of 80% Then go into the illumination settings of the material and give the receive GI a strength of 138%. Then place this material on your floor and give it a rotational setting of H = 78* P = 0* B = 0* and set the projection to spherical.
Setting Up Your GI
Go into your Global Illumination settings and give the following settings, i'm using a standard setting of GI with a strength of 100%, accuracy of 60% a prepass size of 1/1, and diffuse depth of 1, stoachastic samples of 1000 min resolution of 500, maximum resolution of 1500, to recompute the GI first time, to show illumination in the prepass, and identical noise distribution and there's no need to save the GI solution.
This is all you'll need to do to get a good GI compositing scene.
I hope this method transfers well into other applications. If it doesn't i'm not sure what else to suggest i'm afraid.
Below is a test render with some red spheres.

Enjoy & Thanks For Reading.

Classic Gamer

Thursday, 5 July 2007

Classic Gamer - Ambient Occlusion Tutorial

This is a small tutorial on how to create artificial lighting using Ambient Occlusion. Pretty self explanatory. Enjoy CG.

Monday, 2 July 2007

A Little Change Of Scene

I've recently got back into bootlegs/mashups again, not listening to them I mean, no actually making them!I go by the remixer name of Johnny Boot Legs, namely as it's my name, and I thought making an oxymoron out of the Bootlegs Boot Legs thing was funny. The best place in the world for mashups and remixed is GYBO (Get Your Bootleg On) I'm very privledged to be a member and there's so incredibly talent over there, not only better than me but cool people too. I'm not the best remixer in the world but I do enjoy dabbling. So here's a tweakable very very quick bootleg I did today, using Maroon 5's - Makes Me Wonder Versus 80's norweigen legend's A ha's - Living A Boy's Adventure Tale. And so we get the title Wonderous Adventure Tale :) It's a little rough around the edges and it's very short, but I've not done this kind of thing since 2002, it was produced in Sony's Acid 6 sound program. I quite like it. Anyway click on the Z hare link and get it a try! Enjoy CG.