As some of you may have seen, yesterday during the 2009 Blender conference keynote, Ton Roosendaal announced the addition of another full time blender developer: me! Thanks to the support of a very generous anonymous sponsor, I should be able to survive working from home on Blender development for the next few months.

This came about over the last week or two, so it’s still new for me as well. As far as I’m currently aware, the brief for this project is ‘Get Blender 2.5 ready’. So rather than some of the other things I’ve been working on in my own time such as volume rendering, at least in the near term, this project will involve a fair bit of ui work, fixes, tweaks, cleaning up, attacking the 2.5 todo list, documentation - attacking the main things needed to get the 2.5/2.6 work polished to a professional level.

As usual, I did lighting/shading/comp, and some modelling and fur work too. Jeremy Davidson did most of everything else - animation, rigging, particles, etc. In general it went pretty smoothly, although some of the bigger shots full of trees and houses caused some headaches with the amount of geometry. Especially since at the start of the project we were using 32bit systems to render, though we ended up moving to 64bit midway. Only the first few visible ‘layers’ of trees are geometry (well even still, geometry with branch alpha mapped image textures), but after that, much of them are either image planes with baked colour/normal/alpha maps. All in all though, I’m pretty happy with how it turned out.

I’ve also had some behind-the-scenes help in the form of code review and some new features from Alfredo de Greef, which has been great, and last week I bit the bullet and redid part of the shading code. It was previously using a custom method left over from initial experiments that wasn’t entirely physically correct - the shader didn’t conserve energy. In the real world, if more light is scattered out of the volume, towards your eye, there will be less left to keep penetrating through the remainder of the volume, but the previous method didn’t account for this.

In reality this also applies on a wavelength-dependent basis too, if the media is such that the red light is scattered out of the volume (from an initial white light shining on it), all that’s left to continue through the rest of the volume is the inverse of that (roughly cyan). I got to work changing this in the code, but after a long time testing realised it was getting very difficult to control. Most of the time, if you’re making a coloured volume (like the excellent coloured smoke in the Cloudy trailer), you want to be able to just set a colour and be done with it. Doing it by tweaking wavelength dependent absorption and scattering was getting to be a real pain, so I ended up chopping and changing things around.

Now there’s a single physically based ’scattering’ parameter, controlling the amount of light that’s scattered out of the volume (leaving less to continue through), as well as a ‘transmission colour’ that defines the result colour in the rest of the volume, after out-scattering and absorption. With these settings, by default, the shader works physically correctly. For ease of control though, I also added a ‘reflection’ colour and strength which basically acts as an RGB gain, tinting the out-scattered light. It’s more of a non-physical tweak, but it does make life a fair bit easier. I’ve documented these settings with example renders on the blender wiki.

I’m pretty happy with how it’s working now: physically correct by default, but with the option of changing it for artistic control, and philosophically I think that’s how it should be. One of the many things I dislike about Blender’s current shading system is that it generally starts out incorrect, and you have to really understand what’s going on, and work quite hard in order to make it do the right thing (energy conservation, obeying physical laws, etc.). Not only is this a real pain since you have to go through the same chores every time just to get a decent looking material, but for many people who don’t have a good understanding of how rendering/shading works (or should work!) they’re left with sub-par results since they don’t know what magic buttons to press. You should have to work to break it, not to get just a base level of correctness. In further work I do on shading/rendering, that’s going to be a large motivation, to get things working physically plausible by default, but with the ability to break the rules if the situation requires it.

Please have a look below, or on Vimeo. Details on the reel page. Thanks!

Today I moved to a contract position at Red Cartel, so I’m now available for freelance projects. I’ll continue to work with them as needed, but this means I’ll also have down-time available to work on other things on a contractual basis, such as 3d artwork/animation, scripting, or blender development.

My birthday was last week, and I have a new toy! Kat managed to hunt down from ebay a Mamiya c330f (shipped from Pakistan!) medium format twin lens reflex. Thanks! :) I’ve had my seagull (below, right) for a few years now, and it’s been lots of fun and served me well. It was already a cheap knockoff camera though, and ever since I broke the ground glass focusing screen and did a dodgy fix, replacing it with tracing paper, it just hasn’t been quite right.

In the last month our studio ProMotion (now RedCartel) has had a few nice magazine writeups. We’ve got multiple page articles in both the September issue of 3D World magazine and August issue of Desktop magazine, so go check it out!

If you’re subscribed to this site’s RSS, you may have noticed me gradually cleaning and putting online photos from my Morocco trip. Well, they’re finally all up on flickr (or at least the ones worth looking at!)

Earlier this week, I got a CT brain scan done, to get checked out for peace of mind after a sickness-induced seizure I had while away in Morocco. Fortunately, the result came back completely clean and normal, which is great, but as a nice bonus they also gave me the CT scan data on CD. So of course the first thing I did was load it up in OsiriX, have a look, and generate slices to load up in Blender!

Images from OsiriX:

Image slice voxels in Blender:

There are some other new features and optimisations mentioned in the commit log too. I really hope this helps people involved in medical visualisation/research, if only by providing them a free method for making animations with case data. If you are in the field, I’d love to hear from you.

Some test renders:

Made a simple little script last night for testing voxel data loading - it creates vertices of a mesh based on voxel data, if the voxel’s value is above a threshold. The file’s here if you’re interested. The datasets this works with are available here.

A few weeks ago, I returned from about a month spent in Morocco with Kat. Apart from a minor incident - splitting my eyebrow open after having a food poisoning-induced seizure on the floor of the bathroom in the middle of the night, everything was great. It’s a beautiful, ancient country of amazing extremes, the people were kind and welcoming, the food delicious.

We’re here to discuss and hopefully make some decisions and consensus on the work we’re doing for Blender 2.5, particularly regarding the user interface and new tool/event system. It’s been really promising so far, and we’re agreeing on a great number of things.

A few links:

• Some photos at the Blender Institute by Andy
• Live audio feed via skype
• ‘Winter Camp Warm Up’ video recorded at the Blender Institute
]]> http://mke3.net/weblog/winter-camp-09/feed/ http://mke3.net/weblog/winter-camp-09/ http://feedproxy.google.com/~r/mke3net/~3/wtIeNXp04sw/ http://mke3.net/weblog/lighthouse-tornado/#comments Sat, 24 Jan 2009 04:19:16 +0000 Matt http://mke3.net/weblog/lighthouse-tornado/ Last week I went to see a few sessions of the 2009 Sydney festival called films afloat, a free outdoor film screening on a massive screen floating out in the middle of Darling Harbour. Before the main feature (each night a different movie, with a soundtrack played by an improvising live band!) they showed the finalists of the animation competition, which our short ‘Lighthouse’ was included in. We ended up coming second in the competition, which was nice, but even better just to have it shown outdoors in front of a few thousand people in such a great atmosphere.



At work we also published a project we finished late last year, which was our first production use of the volume rendering tools I’ve been working on. It’s just a couple of shots, produced for an internal corporate video involving a hallucination sequence where a worker gets ripped out of his cubicle by a tornado. It’s a bit silly, and may not be the greatest vfx shot known to man, but it was fun to do, and good to give the rendering tools a good hammering in a practical context. There’s a bit more info about the process in this blenderartists thread.



]]> http://mke3.net/weblog/lighthouse-tornado/feed/ http://mke3.net/weblog/lighthouse-tornado/ http://feedproxy.google.com/~r/mke3net/~3/c61LnXDl-9Y/ http://mke3.net/weblog/radiohead-point-density/#comments Sun, 11 Jan 2009 01:00:05 +0000 Matt http://mke3.net/weblog/radiohead-point-density/

I’d heard before about Radiohead’s House of Cards video, made entirely from 3D laser scan data. Yesterday I found out that some of the point cloud data files were made available to download from Google under a creative commons license.

So I did a little test reading it into Blender with a quickie Python script, and rendered it as a volume, using the ‘point density’ texture, in the sim_physics branch. You can
download the .blend file including the script.




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