Everyday 3D

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!

Augmented Reality (AR) generated so much buzz in the community in the last few weeks that I had to give it a try!

I suppose most of you know what AR is, however just in case you don't, here's some basic facts from an Actionscript developer perspective: augmented reality uses pattern recognition to render 3D graphics on top of a video display. A pattern, also called marker, is a rectangular shape that you need to print and position in front of your camera. The stream from the camera is analyzed and the marker is used to determine the coordinate system of the world captured by the camera. This coordinate system is passed to a 3D engine which renders objects on top of the video image. Pretty simple, huh?

As far as Flash is concerned, the API for augmented reality is called FLARToolkit, which is an AS3 port of library written in Java and C done by Saqoosha. If you want to know more about this project, here's a great intro to the subject written by Mikko Haapoja.

In most of the cool AR projects I have seen so far [1] [2] the user is supposed to hold the marker and move it around in front of the camera and the 3d object follows the marker. I had a slightly different idea: why not just leave the marker and the camera in one place and use your keyboard to move around the 3d objects?

Some time ago I posted a demo featuring a Mustang that you could drive around a desert scenery. I thought it would be cool if I could now drive it around my bedroom floor. I was very surprised how easy it was to integrate my model with FLARToolkit and Papervision3D. All I had to do was to scale and rotate the model a bit and that's it!

The above video shows a recording of the experiment. If you have a webcam you can try it yourself. To do this, follow this instructions:

1. Print the marker (You can alternatively display it on your iPhone)
2. Click on this link, and choose "Allow" from the security dialog
3. Point your webcam so that the marker is fully visible
4. When the car is loaded (~250kb) it will appear on top of it
5. Use cursor keys to drive the car and CTRL key to apply hand brake
6. Have fun!

If you want to dig further here's the source code. The whole magic is in the FlarMustang.as class. The rest of the classes are an adaptation from the FLARToolkit basic example and some classes I used for the Mustang demo.

Unrelated note. In case you are reading this post in your RSS reader, you might not have noticed that I redesigned the blog. It's good to change from time to time! Among other stuff, there's a new list of previous 3D experiments and new links in the blogroll, so take a look.

Demos: [ 1 ] [ 2 ] [ 3 ] [ 4 ]      Flash Player 10 required (obviously)

Flash Player 10 has been around for a few months now. As most of you know, it brings some native 3D support. It's not as robust as Papervision3D or Away3D, and in fact was not designed to compete with those engines. Rather than that, it contains classes that perform 3D calculations and allows basic 3D manipulation of display objects.

The last months I focused on catching up with 3D math. I ordered a book called "3D Math Primer", which explains in detail all the vector and matrix operations involved in 3D graphics. Even though the examples are in C++ I recommend this book to anyone doing 3D in Flash. The authors made a great effort to explain the subject with clarity. It worked pretty well for me and I understand the math behind 3D much better now.

Both Papervision3D and Away3D were created so that we don't have to deal directly with 3D calculations. If you are working on a project that involves non-trivial 3D and has a deadline, it's better to choose one of those engines instead of "pure Flash Player 10".

However, if you just want to do some casual experiments and learn something on the way, FP10 is great. It offers a small number of tools, focused around Vector3D and a Matrix3D classes. These classes offer low level functionality, so to use them one needs to understand what's going on under the hood. This is a great way to learn!

Then I had this idea to port AS3Dmod to Flash Player 10 and try to run the modifiers on objects created using FP10 3D classes. It turns out it was not so difficult. Instead of rendering textured 3D objects I just render a single pixel for each vertex. Thanks to this I get a relatively good performance even with as much as 8000 vertices. I found that a modifier applied to such a large amount of vertices, gives interesting visual effects. I even wrote a very simple Wavefront OBJ importer, and I could import the 3d pants model from one of my previous posts to render them in Flash Player 10.

All my previous demos with AS3Dmod involved pretty small amount of vertices - most often no more than 500-600. At this level the performance of the modifiers was not a problem. But with 8000 vertices the modifiers start to have an big impact on the frame rate. A Perlin modifier alone takes 4-5 FPS, which is quite a lot and it got me worried. I believe code optimizations are in order. An interesting solution could be to implement the modifiers as a Pixel Bender kernels. Anyway, I need to do some more research...

In the AS3Dmod SVN you'll find the FP10 branch. The main difference between this version and the trunk is that it uses FP10 built-in Vector3D and Matrix3D classes as well as Vectors instead of Arrays. The sources for all experiments mentioned above, including a simple AS3Dmod plugin for FP10, are available here.

Take a test drive with a powerful Mustang GT in a desert scenery! This demo features a car model imported from Maya into Papervision3D. It uses some home-made physics to simulate the car movement and a couple of new AS3Dmod features to manage the model (more below).

I created this demo together with Krister Karlsson. Krister is a 3d artist working with Maya and founder of Modesty - a Stockholm based creative agency. The (super)low poly Mustang used here is based on a concept model made by Krister that was later used to create an actual car! You can read more about this project here.

Working with this demo has been an occasion for me to explore all the spectrum of Flash 3D related development, like importing and managing a complex model, adding interaction and scripting car physics. All this with a reasonable performance in mind, of course.

There is quite a lot of source code involved in this demo. I won't be publishing it all as parts of it are rather messy. Instead I'll focus on some particular problems I've encountered and solutions to them.

Pivots. I can't tell if this is a problem of the Maya Collada Exporter or if we have been doing something wrong, but the fact remains that moving the pivot point of an object in Maya is not reflected in Papervision3D. Instead, all pivot points default to the center of the whole object when the DAE file is imported.

To fix it, I had the idea to move the pivot point in Actionscript. Unfortunately, there isn't an easy way to do that in Papervision3D. This problem is generally solved by putting the DisplayObject3D inside another and move it in relation to its parent. But when all the objects are part of a structured DAE it becomes quite painful and requires additional steps. So instead, I wrote a modifier that takes care of that. It's called Pivot, and this is the way it works:

This piece of code will move the pivot point -200 units on all 3 axes. In case of this cube it will end up in the lower left corner. It does it without creating any additional display objects, but rather by offsetting all the objects vertices.

Please note that I collapse the stack after applying the pivot. Otherwise the pivot would be moved at every call to stack.apply(), which is not what we are looking here for.

The problem with the Mustang model was that all 4 wheels were rotating around the center of the car rather then around individual centers of each object. I needed to move the pivot point to the center of each wheel. I thought that moving the pivot to the geometrical center of the object is a typical thing to do, so I create a shortcut method for it:

Calling this function automatically sets the pivot point in the geometrical center of the mesh. At this point I thought I was done with the wheels, but there was one more problem...

Roll & steer. I think anyone who ever created an interactive 3d car model must have faced this one. A wheel rolls around the Z axis and the steering goes along it's Y axis. So, the first think that came to my mind when I started to code it was:

While this code seems perfectly logical, when put in action things go wrong and the wheel starts to act like if the car had undergone a severe crash.

The reason for this is that once the wheel rotates along the Y axis (turns), the Z axis is no longer the right axis for roll. The correct axis would be the Z axis rotated 30 degrees on the XZ plane.

Again, a solution would be to enclose the wheel into a parent DisplayObject3D and then use the parent to steer and the child to roll. However, since I had already an elegant solution for the pivot I didn't want to clutter my model with an additional set of elements for this one either.

There comes the Wheel modifier. Apply it to an object - typically of a cylindrical shape - and use its speed and turn properties to manipulate the wheel.

Internally the modifier applies some math to rotate the roll axis according the the current turn value so that everything looks fine and you don't need to worry about it ;) Read the documentation of this class for more information.

All this new features are available in the latest SVN revision of AS3Dmod. So, go ahead and grab it later. But first, enjoy your ride!

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!