mke3.net / Footprints in a digital world by Matt Ebb

essaouira harbour-4 [Flickr]

mattebb — Fri, 03 Jul 2009 02:36:56 PDT

mattebb posted a photo:

essaouira harbour-3 [Flickr]

mattebb — Fri, 03 Jul 2009 02:36:41 PDT

mattebb posted a photo:

seagulls from seagull [Flickr]

mattebb — Fri, 03 Jul 2009 02:36:15 PDT

mattebb posted a photo:

essaouira harbour [Flickr]

mattebb — Fri, 03 Jul 2009 02:35:51 PDT

mattebb posted a photo:

wall painting [Flickr]

mattebb — Tue, 30 Jun 2009 22:37:08 PDT

mattebb posted a photo:

near the essaouira jewellery souk

Links for 2009-06-29 [del.icio.us]

Tue, 30 Jun 2009 00:00:00 PDT

Standards - ColourWiki

Links for 2009-06-26 [del.icio.us]

Sat, 27 Jun 2009 00:00:00 PDT

Gamma error in picture scaling

Links for 2009-06-24 [del.icio.us]

Thu, 25 Jun 2009 00:00:00 PDT

GigaVoxels : Ray-Guided Streaming for Efficient and Detailed Voxel Rendering

using image slice voxels

Matt — Wed, 24 Jun 2009 02:42:13 +0000

Here’s a quick screencast showing how to use the voxel data texture to load and render image slices as 3D volumes. It may be a little unclear in this small window, but you can click through to Vimeo to see the HD/fullscreen version. This is using the sim_physics branch in blender SVN, you may be able to find builds for your system on graphicall.org.

medical voxel data

Matt — Sat, 20 Jun 2009 06:50:13 +0000

Today I committed some new additions to the blender sim_physics branch, making it easier to load up different types of voxel data sets for volume rendering within Blender. The most significant addition is a new ‘Image Sequence’ file format choice in the voxel data texture, which makes it easy to load up image slice sequences as the Z axis of a 3d voxel grid.

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:

Links for 2009-06-11 [del.icio.us]

Fri, 12 Jun 2009 00:00:00 PDT

3DMagix: re-branding and selling the free software Blender | BlenderNation

voxels -> vertices

Matt — Wed, 10 Jun 2009 22:05:37 +0000

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.

I’m working on adding support for these, and also image sequences ( 3D voxel resolution = image X * image Y * number of frames), in Blender’s voxeldata texture, which should be interesting for people wanting to load up medical data. A preview animation is on vimeo.

Links for 2009-06-03 [del.icio.us]

Thu, 04 Jun 2009 00:00:00 PDT

Efficient Spherical Harmonics Lighting with the Preetham Skylight Model

gecko tvcs

Matt — Wed, 27 May 2009 01:48:57 +0000

Some recent Bridgestone Gecko TVCs @ ProMotion. I did shading/lighting/comp.

morocco

Matt — Sat, 23 May 2009 00:58:23 +0000

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.

I’ve been slowly putting a few photos on flickr - so far there’s Casblanca, Rabat and Chefchaouen. More on their way. It was great to take the seagull out for a spin, although it seems the focus on it isn’t so accurate any more after I accidentally broke the ground glass screen and replaced it with tracing paper to keep it in action. Perhaps it’s time for retirement.

Links for 2009-05-21 [del.icio.us]

Fri, 22 May 2009 00:00:00 PDT

Links for 2009-04-26 [del.icio.us]

Mon, 27 Apr 2009 00:00:00 PDT

CG References & Tutorials
lots of renderman stuff

Be back soon

Matt — Wed, 25 Mar 2009 22:38:14 +0000

I’m going to be away for a few weeks, this time for fun. I’m leaving phones etc behind and email contact may be a bit limited. See you later!

Winter Camp 09

Matt — Thu, 05 Mar 2009 08:46:38 +0000

I’m currently here with several other Blender developers at Winter Camp 09, organised by the Institute of Network Cultures in Amsterdam.

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:

lighthouse / tornado

Matt — Sat, 24 Jan 2009 04:19:16 +0000

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.

Radiohead / point density

Matt — Sun, 11 Jan 2009 01:00:05 +0000

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.

new news

Matt — Sat, 29 Nov 2008 23:19:51 +0000

It’s getting to the end of the year and things are getting busy. There’s been plenty on at work - quite a few projects have been running concurrent for a while, including a new Bridgestone gecko spot that’s out now, and the still in-progress project I’ve been working on the volume rendering for.

We’ve been getting around a bit too, four of us headed down to Melbourne in October to attend the first ‘Melbourne Blender Society‘ meeting. We gave an informal presentation about some of our work, much of it involving character setups, and then headed out for some ‘beer r&d’, meeting some fun and interesting people (Hi Glenn, this only took a month ;).

Jez, James and I also gave a presentation at the Digital Media Festival in Sydney , on the topic of ‘an open source pipeline’, talking about our use of Blender in production. Some of the parts that interested the audience of mostly 3d/vfx/design people most were existing features like the library linking system, but also the ability for us to do custom development, such as contracting the ocean sim tools for the Lighthouse project. I also showed off some work on the volume rendering too ;)

The volume rendering tools are at the point now where it’s going to give acceptable results given the timeframe. Although it’s still lacking a bit in some areas right now that aren’t a priority for this job, for my purpose it’s going pretty well. Raul has now picked up this code to work with too, and I’m looking forward to seeing his implementation of voxel data sets. A couple of the improvements I’ve made since last time posting include:

Particle rendering
There’s now a new 3d texture called ‘point density’ that retrieves density and colour information from point clouds (either particle systems or object vertices). It uses a BVH tree to store the points, and looks up what points are within a given radius of the shaded point, with various falloffs. It also has a few methods for simple turbulence, adding directed noise to give the impression of more detail. It’s also possible to use this texture on solid surfaces too.
Light Cache
In order to speed up rendering of self-shaded volumes, there’s a new option to precalculate the shading at the start of the render into a voxel grid, which gets interpolated later to generate lighting information, rather than shading the lamps directly. You could make the analogy to raytraced occlusion vs approximate occlusion in Blender - it often gives around a 3x speed up with similar quality.
A few other small things such as internal and external shadows, anisotropic scattering with various phase functions, integration with the sun/sky system, and various fixes.

Kajimba’s also rolling along nicely. We’ve released several more animation tests with audio (and plenty more sill in the pipe), the voices for the first episode have been recorded, and the animator dudes have started working on lipsync tests to begin some animation on ep 1 soon.

And on it goes…

grogan enters

Matt — Tue, 28 Oct 2008 08:22:02 +0000

We’ve put the first animation test from Kajimba online (with audio), check it out! :)

There’s a few of these clips coming down the pipe, so stay tuned.

Blender Conference 2008

Matt — Sat, 25 Oct 2008 00:05:36 +0000

As much as I’d love to be at the 2008 Blender Conference in Amsterdam, as I have in some years past, it’s quite prohibitive and difficult, especially with work. Luckily, there is a live feed to watch the presentations online. One presentation that I’ve watched in its entirety so far is by William Reynish: The evolution of Blenders User Interface. I’ve met William a few times, and we’ve chatted about these issues a long time ago, and his presentation brilliantly elucidates so many things that I’ve been thinking about, ranting about and very patiently waiting to start working on, for several years. Do yourself a favour and watch it now!

These issues are not theoretical niceties, they’re serious problems that I (and the other people I work with) run up against day by day in our production work. They’re hurdles in Blender’s workflow that not only make Blender slower and clumsier to work in than it could potentially be, but also harder for professional users of other software to come up to speed in Blender quickly, which is important for us too. I’m sure William has come to the same conclusions after his experience working on Big Buck Bunny. Anyway, I want to offer my full support behind William’s presentation, and during the work on Blender 2.5 I’d like to do whatever I can to help make that happen. I hope you all can give these ideas the same support too.

volume rendering updates

Matt — Wed, 24 Sep 2008 10:24:16 +0000

Luckily, I’ve been able to work full time for a while on the volume rendering code, as part of budgeted R&D time at work. Since Monday I’ve made a lot of progress, and have been committing code to the ‘sim_physics‘ SVN branch, maintained by Daniel Genrich.

I’m actually quite surprised at how quickly I’ve managed to come this far, I guess I can attribute it partially to the clear design of pbrt, which I’ve used as reference for the fundamental structure. So far, I’m getting close to having it at a reasonably well integrated state with the rest of the renderer. Perhaps tomorrow it’ll be at a state where particles could be rendered by just instancing spheres at each point.

Some of the changes so far include:

Fixed the shading bug I mentioned earlier, due to a limitation in the raytrace engine (before, after). Now shading works quite nicely.
Added colour emission - as well as the overall ‘Emit:’ slider to control
overall emission strength, there’s also a colour swatch for the volume to emit
that colour. This can also be textured, using ‘Emit Col’ in the map to panel.
Cleaned up and clarified volume texture mapping, fixing the offsets and scaling, and adding ‘Local’ (similar to Orco) mapping, alongside Object and Global coordinates
Added colour absorption - rather than a single absorption value to control how much light is absorbed as it travels through a volume, there’s now an additional absorption colour. This is used to absorb different R/G/B components of light at different amounts. For example, if a white light shines on a volume which absorbs green and blue
components, the volume will appear red. This colour can also be textured.
Refactored the previous volume texturing code to be more efficient
Worked on integrating volume materials into the rest of the renderer. Now other objects (and sky) correctly render if they’re partially inside or behind a volume. Previously all other objects were ignored, and volumes just rendered on black. The colour of surfaces inside or behind the volume gets correctly attenuated by the density of the volume in between - i.e. thicker volumes will block the light coming from behind.
Enabled rendering with the camera inside the volume.

Correct shading and absorption	Shading with two lamps	Shading within clouds density texture
Textured (with colour ramp) emission colour	Example of various absorption colours	Textured absorption colour
Objects and sky inside and behind volume	Shaded concave volume	Camera passing through a volume

Kajimba

Matt — Thu, 18 Sep 2008 10:08:50 +0000

This week, it’s been very exciting to publicly show a project that’s in the works for some time: Kajimba. It’s a CG animated comedy series for mature audiences (though not pornographic!) about a ragtag bunch of animals in the distant Australian outback, hanging out at the only pub for thousands of km. Kajimba has been in progress in-house at ProMotion since before I started working there, but in the last year has finally gathered momentum, going from what was originally a concept, some sketches and a few early character models, to now, where we’ve done a good few minutes of rendered character animation tests, and production on the first (out of 26 slated) 5 minute episode has begun.

At the present, it’s self-funded by the studio, so it’s taking time to develop alongside other paid work. The benefit of this is that we can do what we want, which working out great so far. It’s not certain how the episodes will be delivered, whether it gets picked up by a TV network or if we’ll try something different. At this stage, we’ll concentrate on getting a first episode done and see how we go from there. It’s a great concept, very aussie, and very exciting. We should hopefully have some first voice recordings happening soon along with more and more images and animation tests coming down the wire so keep an eye on the blog and check on our progress!

Volume Rendering

Matt — Wed, 10 Sep 2008 00:47:14 +0000

Some of you may be aware of the great work done so far by Raúl Fernández Hernández (”farsthary“) concerning volume rendering in Blender. For those not in the know, rendering volumes of participating media as opposed to solid surfaces, has many uses such as realistically rendering smoke, fire, clouds or fog, or even with more complicated techniques, rendering volume density data such as MRI scans for medical visualisation.

Raúl completed a fair bit already, implementing this in Blender. Living in Cuba, where he doesn’t enjoy the same kind of connectivity as in many other parts of the world, it’s been difficult for him to participate in development and share his work. A few weeks ago, he emailed me asking for help with his code, and with maintaining it publicly. I promised I’d at least have a look at the first patch he was able to release and see what I thought.

In some spare time, I had a go at taking apart his patch. Unfortunately, it became clear that it wasn’t suitable for immediate inclusion. It was Raúl’s first time coding in Blender (or perhaps in 3D) and due to this, wasn’t aware of some of the techniques available to make his life easier, or of how to integrate the code as cleanly as it could or should be. On top of this, working alone without being able to easily communicate with other developers, he’d been working hard on adding more and more features and options on top of a structure which I think could be done differently and a lot cleaner at a fundamental level. This led to some quite complicated code, and a tricky UI for artists to interact with.

I proposed to Raúl that I start again from scratch, simpler and more cleanly integrated and then merge in what I could later down the track, step by step, to which he was very enthusiastic. He excitedly agreed with my invitation to work closely on integrating things like the simulation work he’s been doing, once a new structure is well defined. Recently in a few days off from work I sat down and started fresh, based on the approach in Physically Based Rendering.

Spot light in constant density volume

3 point lights in constant density volume

Textured spot light in constant density volume

So far I’ve got it working reasonably well with about 90% new code. Unlike before, it’s following a physically based approach, with a region of constant or variable density, calculating light emission, absorption, and single scattering from lamps. My aim is to get a simple, easier to use version ready, optimised for practical rendering tasks like smoke, fire or clouds. Once this is working perfectly, integrated cleanly and completely, and working in Blender SVN, further down the track we can think about adding some of the less common capabilities like isosurfaces or volume data sets.

Cloud texture controlling density, lighting from volume emission only

Cloud texture controlling density, 3 lights with single scattering

Spherical blend textures controlling density, directional light with single scattering

There’s still a lot to do - there’s one remaining bug with single scattering I must try and track down, and then there’s a lot of integration work to do, calculating alpha, rendering volumes in front of solid surfaces etc. Before too long I’ll commit this to the newly created ’sim/physics’ SVN branch and work on it in there. I don’t know how long it will be before Raúl is able to start working on this again too, since he’s under some horrible circumstances after hurricane Gustav ravaged Cuba. At least in the near term, I’ll be able to continue poking away at this in SVN.

Some things on my want-to-do list include:

Plenty of optimisations
Adaptive sampling - step size and/or early termination
Alternative anisotropic phase (scattering) functions such as Mie or Henyey-Greenstein
Wavelength (R/G/B) dependent absorption, so light gets tinted as it travels through a medium
An optimised bounding box or sphere ‘volume region’ primitive, which could be much faster than raytracing meshes as is done now
Multiple layers deep ray intersections, to enable concave meshes or volume meshes in front of volume meshes
Rendering Blender’s particle systems, either by creating spherical ‘puffs’ at each particle as Afterburner or PyroCluster do, or perhaps by estimating particle density with a kd-tree or such

I hope to be able to provide some more updates on this before too long!

Linear Workflow

Matt — Fri, 05 Sep 2008 02:10:40 +0000

I recently posted on blenderartists.org in response to some questions and misunderstanding about gamma correction and ‘linear workflow’ in 3D rendering.

I thought I’d re-post it here, since there are a lot of misconceptions about this topic around.

Much of the value of a linear workflow comes with rendering colour textures. But as the name suggests, it’s a workflow, that has to be kept in mind throughout the entire process.

The issue is that when you make a texture, either painting it in Photoshop to look good on your screen, or as a JPEG from a camera, that image is made to look good under gamma corrected conditions, usually gamma 2.2. So as you paint that texture, you’re looking at it on a monitor that’s already gamma 2.2, which is not linear. This is all well and good, displays are already gamma corrected to better fit the range of human vision.

The problem starts though, when you use those colour maps as textures in a renderer. When you’re doing lighting calculations in a renderer, those take place in a linear colour space. i.e - add 2x as much light, and it gets 2x brighter. The problem is that your colour textures aren’t like that if they’re at gamma 2.2. What’s double in numerical pixel values in gamma 2.2 is not necessarily twice brighter perceptually. So this breaks the idea of taking brightness information from a colour texture and using it in lighting/shading calculations, especially if you’re doing multiple light bounces off textured surfaces.

So what a linear workflow means, is that you take those colour textures, and convert them back to linear space before rendering, then you gamma correct/tonemap the final result back to gamma space (for viewing on a monitor). Now the lighting calculations work accurately, however it does change things - because the textures get darkened in the midtones the image can look darker, so you need to change the lighting setup, etc. etc. Hence, workflow - it’s something you need to have on all throughout the process, not just applying gamma at the end.

I wrote some code a little while ago that did it all automatically in the shading process, applying inverse gamma correction for colour textures before rendering, then corrected back to gamma 2.2 afterwards. After adjusting lights from old scenes to have the same appearance, it gave some nice results. It seemed to bring out a lot more detail in the textures, which got washed out before (left is normal, right is with linear workflow). It’s not finished though, it also needs to adjust the lights in the preview render, and inverse gamma correct colour swatches too so the flat colours you pick in the UI are also linear.

Further references:

Striderite Slimers

Matt — Thu, 04 Sep 2008 10:29:06 +0000

We recently finished a 15 second commercial for Striderite Slimers a new childrens’ shoe made in conjunction with Nickelodeon in the US. It involved heavy use of fluid sim, with all the sim, animation and rendering done in Blender.

You can see some images and video at our website below, and also a zoomed out openGL view of the big splash. The project has also been featured on It’s Art Magazine, and BlenderNation.

Olympic Appearance

Matt — Sun, 17 Aug 2008 09:34:53 +0000

While watching the Beijing olympic opening ceremony last week, I got a bit of a surprise. A couple of months ago at work, we had a quick project come in to model, texture and render turnarounds of a few Chinese artifacts from a reference photo each. Mine wasn’t a big job and was pretty fast to do, using some texture projections with the UV Project modifier and cloning and cleanup in Photoshop.

We’d had a hunch it may be for something related to graphics in the olympics, but I was taken aback to see it blown up on the enormous LED screen during the opening ceremony. I wonder how many million people saw it - too bad this tiny part wasn’t something a bit more impressive! :) Still, not bad for the novelty at least! Below is the original render, and a grab of how it appeared on screen.

blatant self-promotion

Matt — Tue, 22 Jul 2008 02:22:00 +0000

A couple of nice things have come up lately that I’m quite proud to be able to mention. I was at the Museum of Contemporary Art on the weekend checking out part of the 2008 Biennale of Sydney. Browsing in the museum shop afterwards, I came across a book with a familiar sounding title - Design and the Elastic Mind, published by MoMA (that’s right, the Museum of Modern Art in New York). I knew Elephants Dream had been featured in the web component of this exhibition a little while back, but had no idea there was a book. So, I took a look inside and there it was, published art, with our names in the index too!

Another nice piece of news came in from Exopolis yesterday, mentioning that Lighthouse had appeared in Shoot magazine’s Summer 2008 top 10 visual effects and animation chart, coming in at 2nd place! Because of this, there’s also an article on the project too. Not only is this very flattering to see in itself, but especially looking at some of the other names below us, such as The Mill, Framestore, Digital Domain and Psyop, all huge studios with great reputations, it’s very satisfying to see that our little team is in such esteemed company.

Lighthouse

Matt — Mon, 30 Jun 2008 22:29:18 +0000

Last week, Lighthouse was released online, a short film project that our studio had been working on for the last couple of months. The full details about the project, with the movie itself viewable online, high res stills, and production breakdown video are available in the post we made at CGTalk, so please do go and check it out there. The response so far has been great, we got featured on the front page of said website, and have had several thousand views with very encouraging comments.

Although it was a bit tricky for me, being the bottleneck responsible for the texturing, shading, lighting, comping, with a couple of weeks of late nights towards the end of the project, it was quite enjoyable overall. Exopolis, our clients in LA, were fun guys to work with and gave us a lot of room to work without being micromanaged. It’s interesting that Liberty Mutual (the insurance firm who commissioned the work, in the form of the ‘responsibility project‘) are now spending their marketing dollars on producing themed art, rather than usual commercials. It’s certainly the kind of work I’d love to be doing more of.