Everyday Flash

I am proud to announce my latest project. It’s a 3D racing game done in Flash with Away3D. I worked on this project together with Calisto Labs and our client was Snowball Media. My task was to create the 3D game part. It was great fun to work on this project. The team at Calisto Labs did a awesome job and everything went smoothly!

The project required to use my Actionscript and 3D modeling skills together on a scale like I never did before. I spent a lot of time with Blender and Unity in the last months, and without this experience I feel the project would be beyond my abilities. Also, having a direct comparison between Flash and Unity allowed be to see things in a larger perspective.

Flash vs. Unity… again

I built the game with Away3D FP10. I must say that Flash 3D has gone a long way since I first started to play with it, and Away3D is a very solid engine. The 2K polygon limitation is a thing of the past, and the correct perspective projection in FP10 makes everything look so much better. The team also added some other crucial features to create 3D environments – ex. frustum clipping.

Before starting this project I was working on a Unity3D racing demo, so I managed to get quite a few ideas on how to build such a thing. However, when I moved back to Flash, I was a bit desperate because I realized how much stuff I got used to in Unity is just not there in Flash. A built-in physics engine would be the most important one.

Home-made physics and collision detection

For physics in Flash I was tempted do use JigLib at first. But soon I found out that JigLib is way too complex, creating a realistic car behavior would be very difficult and it would probably eat too many CPU cycles. I estimated that Away3D will take around 90-95% of available processing power, so there’s no space for any other complex piece of code to run in the same time. I always think that when it comes to 3D in Flash performance is quality, and there is no excuse for poor performance, even if you want something to look “realistic”. So I ended building something very very simple.

Once I got the car driving around, I needed to add some collision detection. In Unity you quickly get used to the fact that any 3d object is a collider which makes collision detection a no-brainer – just implement a listener method and get a call whenever your object collides with another one. And if you need to add realistic collision response, you just make the object a rigid body and there you go! (Ok, you may need to adjust some settings, but still it’s pretty straightforward).

In Flash it seemed like a much more complex task. I was thinking in the lines of creating a system based on the geometry of the track. I started to study curve equations just to realize I wouldn’t make it even if I had a year to complete the project! Then I remembered, that a good way to test collision with complex shapes is a bitmap.

The way it works is that it takes the car’s position and checks against a map of the track that has different colors for different areas – ex. red for the road, green for the sideways and so on… Since it samples only a few pixels per frame and all it does is check their RGB values, it’s lighting fast. Truly, Flash is the art of minimal!

Scenery

The most fun part was to create the scenery. I’ve never tried to import such a large 3D scene into Flash so I wasn’t even sure if Away3D would handle it. It turns out it did handle it pretty well. Instead of using Collada I went with Wavefront (OBJ) format for the meshes as I feel it gave me more flexibility. OBJ is a simple format which makes it a bit easier to see what’s going on while Collada is bloated and overly complex for my taste. I used Blender to model the track and the few objects that you can see around it – lampposts, houses and the tunnel.

Lightning

Lightning is very important in low poly scenes, because it adds a lot of detail and atmosphere to the scenery, without adding any polygons. Even thought the scenery is simple, I ended up having more that 60 lamps. Of course all those lights needs to be baked on the textures, there’s no way to run them in real-time. Blender has a very good texture baking tool and all this works fine for static objects. But what about objects that move, like the car?

For lightning the car, I reused the concept from collision testing. But instead of a collision map I made another one – a light map. Basically it’s a bitmap with white areas where the scenery is lit and dark ones where it’s not. By sampling a single pixel on every frame I can see if the car is passing through a lit area. Then, all I have to do is to apply a color transform on the car texture to make it brighter. Again – a minimal solution, but it works!

Now that you know all about it, go ahead and try it out!

JigLibFlash is a new library for 3D physics simulation in Flash. It is ported from a C++ open source engine. It’s been around for a few months now, and if you haven’t heard about it, you need to catch up!

I believe physics simulation is the next step in the Flash 3D world, so I got very excited when Ringo from FlashBookmarks invited me join the JigLibFlash team a couple of months ago. One little problem: I am perfectly lame when it comes to physics… In this situation, the only logical thing to do was to join the team and learn all the stuff I need to know about it in the meantime. Sounds like a challenge!

Now I slowly fill my knowledge gap. However, I also managed to do some actual work on the library. Together with Reyco we remodeled the API. We started by making it more Flash developer friendly, less C-style and more AS-style. All the methods start with a lowercase letter now, and instead of having to set the position and rotation using vectors and matrices, the new API offers simple getter/setters for properties like x/y/z and rotationX/Y/Z just like in Papervision3D or in the new Flash Player 10 API.

Last but not least, we also created a plugin system to easily integrate JigLibFlash with the popular 3D engines like Papervision3D or Away3D. Now there are specialized classes to interact with those two engines and it should be pretty easy to create a plugin for another engine if one needs. If you worked with AS3Dmod you should notice that the concept is similar to the plugin architecture in there. Update: I just saw in the sources that someone already created a plugin for Sandy3D.

To learn more about these changes you can refer to the tutorial I wrote which is posted on the projects wiki page. Reyco also wrote a great article about this on his blog.

The demo above is my first little experiment with JigLibFlash and Papervision3D. My idea was to integrate a Collada object with the physics system and to add some interactivity to it. I extended the Mouse constraint class created by Reyco to control the racket. I encountered some problems with stabilizing it in the long run. After having bounced the ball a few times the racket starts to rotate as if the constraints were broken… well, I still need to do some research on that.

Source code. You can browse the sources for the demo here.

Links. Some links to get you started with JigLibFlash:

• Official blog, Google code
• Wiki tutorial on new API and Reyco’s article
• Really cool demo by Andy Zupko

PDFBook3D is a Flash application that allows to transform a PDF document into a 3D model, that later can be viewed pretty much like a real book. The product was just released by Powerflasher, and I was involved in creating the front-end 3d Flash part of it.

This application belongs to the family of flipbook engines. I am sure you have seen the classic 2D version of a flipbook at least once. It is widely popular around the web! PDFBook3D replaces this classic piece with a more accurate and realistic 3D version of the effect created with AS3Dmod bend modifier. The bend modifier allows to create paper simulation in Flash, which is something I already posted about back in November.

The application has a rich set of configurable properties, including dimensions of the book (for non typical page sizes) and a number of quality settings to get a decent framerate on slower machines as well. The Powerflasher team created an admin interface to generate 3d books on the fly. You can see it in action here. The product functionality also includes links editor and video embedding. If you are interested in more information please refer to the Powerflasher Solutions site.

PDFBook3D is also my first commercial project made using Away3D. There are a few features in Away3D that made me choose it, but mostly it was the curiosity to try "the other" engine. I must admit Away3D turned out to be pretty cool!

It is most famous for its advanced features like normal maps, path extrudes and bones animation. However, this project does not rely on those advanced functionalities. Most of what I used in here is pretty basic, but still I was able to find some cool stuff.

One very useful feature is being able to assign back material to planes. It might not seem like a huge thing, but since it is used to create the flipping page, it helped me a lot. Actually any mesh in Away3D can have a back material assigned to its faces using the back property of the class:

Notice, that it is not the same thing as having a double sided material - that is, the same material used for both sides of a face. In this case - one material is used for one side, and a completely different one for the other. This is why it was perfect for creating a page of a book.

Another cool feature of Away3D is triangle caching - it is a built in functionality, that doesn't require any extra coding and it can give a significant performance boost. Thanks to triangle caching, whenever the page flip animation is on, the rest of the book that does not move at this moment is not re-rendered at each frame. A similar optimization can be achieved in Papervision3D using render layers, but it's not as easy to use.

Last but not least, I'd like to thank Fabrice Closier from the Away3D team for support and feedback during the project!

An Actionscript-based 3D bone system is something I wanted to do for a long time, but I couldn't figure out how to approach this problem for several months. A few days ago, I finally made a breakthrough. Here's a first demo I quickly put together: a 3D walk cycle.

So far the only way to have a walking character in Flash 3D was to create an animation sequence in a 3D editor and export it as an animated DAE and/or use Cast3D. For sure, this method allows to achieve awesome results, but it is not nearly as flexible as being able to control the animation directly from Actionscript.

So, how does the above demo work? First of all I created a model of pants in Blender. This is the 4th model I ever did with Blender so it not perfect, but is good enough for the job. The important part is that both legs and the waist form a single mesh.

After I imported the model into Papervision3D I applied several Break modifiers to the model. The Break modifier is a new class I wrote for AS3Dmod and is of key importance for this demo. In brief, it allows to apply rotation only to a group of vertices while leaving the rest untouched. The resulting deformation makes the mesh look like it was broken, hence the name.

I created a modifier stack and added 4 Break modifiers to the pants. One for each tight, and one for each knee. The angle for each of them can be modified separately, which allows dynamic animation.

You probably wonder how I did indicate which vertices belong to which part of the mesh (waist, thigh, calf) and how I even know where those parts start or end on the code level. That is crucial in creating an armature and it is also the tricky part. Most of the 3D IDEs, like 3Dsmax or Blender have some kind of visual interface that allows the user to select vertices and attach them to a bone. In AS everything is code, so this is a challenge. I must confess that for this demo I hardcoded some values and did some assumptions to make it work, but I think there is a way to make this task relatively easy or at least possible to apprehend.

In the long run, it would be cool if bones could be exported from 3D IDEs and exposed as objects in Actionscript. As far as I know, there isn't anything like this available for the moment. Away3D supports collada bone animation but, despite its promising name, it serves a different purpose (correct me if I am wrong.)

Let's go back to the demo. Once I had the Break modifiers in place and applied to the correct areas of the mesh, the rest was rather easy. To create a proper walk cycle, I just took Keith Peters' book "Making Things Move", Chapter 13 on Forward Kinematics, and I adapted the code from the examples.

In case you don't know that book, I would strongly recommend getting it. It contains all the essential stuff you need to know, if you want to call yourself a serious AS3 developer. I never leave home without it! There is also a sequel, with stuff for Flash Player 10.

This walk cycle is only a first step to create a bone system in AS, but I wanted to share it with you without spending another few months making it fully featured. Break modifier is available in the latest AS3Dmod SVN repository. I should warn you however that this is a very early version, not really usable for the moment.

Of course, updates are coming so stay tuned!

I did some research in the blogs and on Twitter, and often when someone mentioned AS3Dmod, the recurring theme was the lack of documentation. Yeah... but creating proper documentation is such a difficult task!

First of all, it's hard to find enough free time. Then, even if you find some, most of us, including me, will always find it more fun to write code instead. Eventually, I profited of the calmer period in the last 3 weeks and made some progress with that. The result is the AS3Dmod tutorial.

In the tutorial you will find answers to the following topics:

• how to integrate AS3Dmod with the Flash 3d engines
• how the modifier stack works
• how to create and apply modifiers
• how to animate the modifier properties
• how to use the collapse feature

Beside the tutorial there are API Docs available for some time now.

Another thing are simple interactive demos for each modifier. So far I created it for one: Skew. You can view it here. The demo allows to see all the properties and features of the modifier in action, instead of explaining it in writing. If this concept gets some positive feedback, I'll try to do more of those.

Hope you will find all this useful, and remember that feedback is very welcome (and much needed). And of course Happy New Year everyone!

Texture baking has been known to the Flash 3d community since a long time, but a quick look into Google shows us that it is not a very popular topic. I think it definitely should get more attention. In Flash performance is always an issue, and high quality is always expected by our clients. Texture baking helps to achieve this goal.

In short, it consists of getting all the lightning effects of a material and "burning" them directly on the material itself. After such operation, the lights cannot change anymore, but the material gets a nice effect of depth and it doesn't require any more computations at runtime.

Most of the available 3D software offers a texture baking function. For the demo above, I did choose Blender because it's free (it also has a very weird user interface, but I digress). On the Flash side, it runs on Away3d.

To create a model with baked textures in Flash I followed this steps:

1. Create the 3d model of the chair in Blender
2. Project all the faces of the model on to an bitmap (in Blender its called UV Unwrapping)
3. Paint the texture in Photoshop
4. Import the texture to Blender and apply it to back the model
5. Add lights and bake the texture on to another bitmap
6. Export the geometry with the UV information included (Collada or Wavefront)
7. Export the baked texture as a jpg
8. Import both into Flash and use your favorite 3d engine to render

Each of the steps above could require a separate tutorial, so instead I published some files created in the process to give you a better idea. You can get them here. Please note, that this is only a reference material - it is not supposed to be built or compiled or anything.

Additionally, for those of you who use Blender a nice tutorial on both UV Texture Mapping and Texture Baking is available here.

In the current state of Flash 3D and its overall performance, texture baking is a highly useful technique that allows to achieve very good results. If you do not believe me, take look at some of the most awesome Flash 3d pieces that came out in the last few months:

• Bunker demo by Alternativa3d team (sources available here)
• EcoDaZoo by Roxik

I am sure you've seen them before anyway. They both combine great visual effects with a very high performance. And guess what... in both of them, you'll find baked textures all over the place!