Combustion

Combustion

Ted Boardman tedb@tbmax.com         http://www.tbmax.com


I really don’t like shoveling snow! However, snowblowers are too much noise and trouble and there’s no place for a plow to push the snow so when more than 6 inches falls in a single storm, I have no choice but to push and toss the 100 foot by 20 foot driveway of snow into whatever nook and cranny I can find. With roughly 3 feet of new snow, not including drifting, over the last couple of weeks I’m running out of space. Well, enough complaining…maybe.

That’s partly the reason why I’m a little late with the column this month, but also because I hadn’t formulated a solid topic and December was a month of travel with trips to Las Vegas, Green Bay, Detroit, and Amsterdam along with the snow. Therefore, I’ve decided to try to cover an piece of software you may want to look at.

Combustion Would Get Rid of the Snow

Oops, there I go again. But, while I’m on the subject, I’d like to talk a little about discreet’s Combustion 2. http://www.discreet.com/products/combustion/ It’s a program that you might be aware of that is essentially a compositor for the television industry, that is, it allows you to create different layers of 2D images that take advantage of Alpha channel information to reveal or block images in lower layers. I say essentially because that is the closest software category Combustion falls into and it is often compared with Adobe’s After Effects or Apple’s Shake…with major differences that could be beneficial to many of you. You have clearly seen the results of compositing during the lead in to the nightly news, for example, but there is much more of it that is not so apparent in major movies. The movie Hollow Man used Combustion extensively for many of the special effects.

The main reason I bring up Combustion at this point in time; it’s been out for several years, is because of the drastic price reductions in recent months. I’ve been hearing quotes of under US$ 1000 in the last few weeks. This places the software at a price point where it could be very cost effective for even smaller offices.

Where to Start?

There are a number of ways that Combustion can be applied to a typical architectural or engineering office to enhance productivity. I mentioned that it was a compositing tool with major differences that work to Autodesk VIZ and discreet 3ds max users advantage.

In it’s simplest form, it could be used by VIZ and max users as a replacement for the Video Post module in max that few seem to take advantage of to create more interesting presentations. You can create sequences of still images and/or animations and blend or cut from one sequence to the next with a variety of wipes, dissolves, or fades. Figure 1 shows a screen grab of a recent Combustion presentation I did using the animation timeline to edit the cuts from segment to segment. This allowed me to work in VIZ or max with very short, manageable segments that were easy to change based on the clients wishes without the need to rerender the entire presentation. Some of the segments are composites themselves, with the background rendered as a still image and held over x number of frames with the foreground animation applied over it, again with substantial time savings in the overall rendering.

Figure 1: Combustion with current frame in left viewport, a schematic view of the layering in the right viewport, and the animation timeline showing the offset for some of the segments.

Beyond the simple compositing of sequences, which can be done with cheaper software like Adobe’s Premier quite effectively, I added some effects like glows and lens flares. But these can be done directly in VIZ and max, you say. Yes, but it is more computer intensive to add these effects in a 3D scene, therefore chances are it will not be as productive or easy to change. Remember that Combustion is a 2D program and generally much faster. More on that later.

Naah, Sounds Like Overkill!

You’re right, simple compositing and simple 2D effects would not alone be good reasons to spend the money on Combustion. Let’s look a little deeper.

You may have noticed, but not paid much attention, to the fact that VIZ and max have some rendering features called Render Elements and the file type called .RPF that can have channels that Combustion can access and modify. VIZ and max can also generate Combustion Workspace files automatically to cut down on some of the setup time in Combustion.

Figure 2 shows the Render Elements rollout in 3ds max 5 that allows you to add elements such as reflections, specular, highlights, or shadows for example to be rendered as separate images or as layers within a Combustion file as seen at the bottom of the rollout.

Figure 2: Render Elements rollout for 3ds max and VIZ allows you to render separate images of elements like shadows, reflections, diffuse color, etc. You can also choose to save a Combustion workspace file containing those elements.

In this example I’ve rendered a simple scene as three elements; Diffuse, Specular, and Reflections, and a Combustion workspace file containing all three as separate layers. Figure 3 shows the workspace file in Combustion with the composite in the left viewport and only the Specular file in the right viewport.

Figure 3: Combustion with the .cws file from 3ds max or VIZ. The composite image shows in the left viewport, the Specular image in the right viewport, and the workspace listing at the lower left showing the order of the compositing.

In Combustion you can apply Operators that are roughly equivalent to max and VIZ modifiers in many different ways. Operators can be stacked for an accumulative effect. Figure 4 shows the same image as Figure 3, but with the addition of a Glow operator on the Specular layer. This causes a soft glowing effect to accentuate the specular highlights of the image.

Figure 4: Adding a Glow operator in Combustion to only the Specular layer changes the mood of the scene and allows changes to be seen in real time.

You can disable operators as you can modifiers in max and VIZ. In Figure 5, I have disabled the Glow and added a Gaussian Blur operator to the reflections layer to soften the scene even more. If you have tried to apply blurred reflections to raytrace reflections in max and VIZ you know the considerable increase in render times it requires. Here again, it is adjusted in real time without the need to rerender to see the effect.

Figure 5: With the Glow operator disabled and a Gaussian Blur operator applied to the reflection layer the scene is further modified without extensive test rendering. The composite is in the left viewport and the blurred reflections in the right viewport.

Finally, the addition to the Diffuse layer of a Color Shift operator to increase the saturation and a Find Edges to give a “hidden line” look gives you a small example of some of the stylized effects that can be created. See Figure 6 for the results of that experiment!

Figure 6: The left viewport shows the composite with Color Shift and Find Edges and the right viewport is just the Color shift effects.

At this point you might say that some of those same effects might be able to be applied in Adobe’s Photoshop. True, but what we have trying here works equally well on animations, not just on still images.

So, What Else?

Well, RPF files for one. This is a file type that you can render from VIZ and max that contains embedded information that can be accessed and used within Combustion. Figure 7 shows and example of the setup dialog in 3ds max 5 with several of the channels checked to be rendered.

Figure 7: Ready to render a 3ds max 5 scene as an RPF file. Information on the Z depth, the Object ID, the Coverage, and the Transparency will be embedded into the file for use in Combustion.

In the case of RPF files I can add operators such as Selection operators based on the Object ID number I have assigned to the objects in max through the Properties dialog. In Figure 8, you can see a Gbuffer Selection operator with a Color Correction operator applied, affecting only the selected object, in this case the teapot. The Color Correction operator was used to change both the mid tone and highlight colors of the teapot.

Figure 8: The right viewport shows the marquee of a Gbuffer Object selection operator, which is the teapot object in the scene. The left viewport shows the result of a Color Correction operator affecting only the selection.

True 3D effects can be applied to the 2D RPF files by taking advantage of the various channels embedded in the file as well. For example, 3D fog and 3D depth of field can be simulated from information about the Z buffer depth that I saved to this RPF file. Figure 9 shows the scene with and without fog.

Figure 9: Information stored in the RPF filetype rendered from max or VIZ allows you to create true 3D effects within the 2D image. Here fogging is applied in the left viewport while the right viewport shows the scene up to the Remove Selection operator. Remove Selection was necessary so the fogging wasn’t applied just to the selected teapot.

In the end the scenes must be rendered from Combustion to create the final output files that your presentation will use but because everything is 2D the rendering can go very quickly and network rendering is built into Combustion.

Last…but not Least

While there are many, many more features to Combustion that would interest cgarchitect readers I’ll finish up by mentioning the Particle Systems in Combustion. Again, Particle Systems are a 2D effect that can exist in a simulated 3D space for speed and productivity.

In this example, I’ve added a particle emitter to the spout of the teapot that contains the Shoot Smoke particle system. I’m showing frame 30 of the animated sequence where the smoke has reached its greatest height and width. See Figure 10.

Figure 10: A fully animated smoke particle system has been added to the teapot spout to simulate steam rising from the spout.

For those of you with VIZ who would like to add particles to your scenes, this will do the trick nicely.

In Summary

I am, by no means, competent with Combustion, but I know enough to be dangerous to myself. This has been a very cursory look at it, too.

The program is fairly easy to use once you get over the initial hump of thinking in 2D again, albeit much differently than ever before. There are some good training sources and support forums that will help you with the learning curve and the time has come to look seriously at Combustion as another tool in creating professional and interesting presentations.

A year ago, at a price of around US$ 5000, I wasn’t so sure of the cost effectiveness of Combustion in the mid-range and small offices, but I would recommend you take a look at it to stay ahead of the competition.

Editors Note: Since the receipt of this article Discreet has announced that Combustion will now sell for $995.00US. Visit http://www.discreet.com for more details.

Good luck and have fun

Ted