Hierarchical modeling

Ideas, enhancements, feature requests and development related discussion.

Hierarchical modeling

Postby sascha » Fri Jan 18, 2008 5:16 pm

After fixing some (as always pretty stupid) bugs, I've finally got hierarchical modeling up and running, here are a few screenshots:
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A simple SDS cube with its mesh at level-0 displayed

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The same cube, this time the mesh at level-2 is shown

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After adding ears and a nose by moving a few level-2 vertices

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Back at level-0...

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...we can still modify the base mesh and move some vertices. Note that this also affects the vertices that have been modified on level-2, just like you'd expect.

You can use all the manipulator tools (move/scale/rotate) on all levels. Of course topology changes can only be applied to the base mesh (i.e. you can't delete or add faces on a subdivision level, which should be self evident).
Currently the edit level can be set using a text-input field, but I think it would be best to place a slider somewhere in the toolbar, so that the edit level can be changed quickly.

One limitation right now is that higher-level verices can only be edited for regular control-points (i.e. not for points on a boundary), but this can be fixed.

What do you think?
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Re: Hierarchical modeling

Postby dcuny » Fri Jan 18, 2008 5:49 pm

Very cool. 8) The numbers you're showing make the interface look pretty responsive.

Why have I got this feeling that the "minimal" version of JPatch isn't going to be released until you've got a fairly robust version of a modeler? That's the route that JPatch initially took, and it looks like it's going that direction with this, too.

What do you want to do? :|
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Re: Hierarchical modeling

Postby sascha » Fri Jan 18, 2008 8:34 pm

Yes, thanks, I'm quite happy with it.

As mentioned earlier, I need I kind of "proof of concept" for various features before I'll continue with the animation part. Hierarchical modeling is done now, the only important feature left is changing the topology - so I'll implement a "delete faces" and an "extrude" feature. Everything else can wait.

So, robust: yes - complete: no
Once extrude is working I'll upload a new build to play with, and then I'll start with the bone editor and then the motion curves.
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Re: Hierarchical modeling

Postby dcuny » Fri Jan 18, 2008 9:23 pm

Part of me really wants to see a more complete modeler sooner than later. But I think what's ultimately going to distinguish JPatch will be the animation features, not the modeler (although that's going to be great). So the sooner the project can show animation coming out of it, the better. My worry is that you'll end up working half the year on the modeler, and in that time, people will see JPatch as "just another modeler", and I'll still be itching to do some basic animation stuff, like walk cycles. :|

Still, seeing modeling working is really tempting. :P
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Re: Hierarchical modeling

Postby sascha » Sat Jan 19, 2008 11:31 am

So the sooner the project can show animation coming out of it, the better.

I tend to agree, but...
What I really fear is that without a modeler, people start loading .obj files into the animator. There's nothing wrong with that, but...
Most .obj files available on the net are hi polygon models (with some 10000 vertices or even more) - again this is perfectly ok for a polygon model to achieve a decent level of detail and smoothness, but it will kill JPatch. Not because JPatch isn't well designed, Java is slow, or anything like that. It's simply because JPatch works with subdivision surfaces, and SDS are more complex than simple polygon models (by orders of magnitude). They consume much more memory and CPU cycles. On the other hand, even a model with just a handful of faces is perfectly smooth, and you can create a fairly detailed character with just about 1000 vertices. It will outperform the 50000 vertex poly-model in any way. This is even more true when advanced features like corners, creases and hierarchical modeling are used. And that's what JPatch is optimized for. Potential users need to understand what kind of models JPatch was designed for, but without a modeler and a few tutorials showing how to create such a model this will be difficult.

So basically I can decide whether "people will see JPatch as 'just another modeler'" or as just another slow Java program than can't even deal with their favorite 200000 vertex hi-poly T-Rex model (which of course was a nice 1000 vertex SDS someone exported at subdiv level 4). Or I can simply ignore what "people" will think about it and just go on. But don't worry, there's light at the end of the tunnel. Although the situation looks much like just before I released 0.3 (when I was working to get the modeler up'n'running), the current version was designed for animation from the beginning, and as I said, once extrude is working, I'll focus on bones and animation. After that you can expect to see the modeler and the animator evolve in parallel.
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Re: Hierarchical modeling

Postby dcuny » Sat Jan 19, 2008 7:45 pm

Sascha wrote:Most .obj files available on the net are hi polygon models (with some 10000 vertices or even more)...

I'm not sure that it's so much of a problem. Most programs (like Blender) allow .obj files to be exported at any subdivision level you want. So they can always go back and choose a lower level of subdivision.

You already mentioned that you were planning on handling static (non-boned) .obj files differently. At some point, you'll probably have to add native support for .obj files, too.

You can also have a warning dialog of some sort appear when the user imports a model over a given number of vertices.

Having a native, low-resolution mesh solution hasn't seemed to hurt Animation:Master that much.

...but without a modeler and a few tutorials showing how to create such a model this will be difficult.

I agree. Looking back on earlier version of JPatch as an example, I don't think anyone's going to adopt it until the modeler is complete. But I'm not sure how much demand there is for "yet another SDS modeler". People seem pretty happy with Wings3D and Blender.

Mind you, I think there'll be demand from the existing adopters. I liked the JPatch patch model (except when I'd get stuck), and I expect that new modeler to be equally nice to use. But the JPatch models are really optimized to be used from within JPatch, so I'd be surprised to see people start adopting JPatch without a nice animation component as well. (Although stranger things have happened).

The other thing that the "minimal" version of JPatch should do is create a stable enough version to allow us to start documenting JPatch. Is there a tool which allows Wiki pages to be collected into .html or .pdf format?
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Re: Hierarchical modeling

Postby sascha » Sat Jan 19, 2008 9:09 pm

Is there a tool which allows Wiki pages to be collected into .html or .pdf format?

I have given that some thought. Wiki to html is obvious, but for a nice pdf there's no way around LaTeX. It's quite simple, instead of <h1>, <h2>, etc. in HTML (or their "===" counterparts in the Wiki) you've got tags like \begin{chapter}, \begin{section}, etc. It should be trivial to write a simple perl-script that transforms a structured Wiki document into LaTeX, including all markup (headings, lists, tables, etc.) - perhaps someone else already did the work. If all else fails, one could still cut'n'past the text into a LaTeX document - I just did that with a 150 page MS-Word document at work, and it's not that difficult. LaTeX supports png bitmap images, as well as (e)ps and pdf vector drawings, and is extremely good at typesetting mathematical equations. There's also hyperlink support for pdfs, so the resulting pdf can both be printed and used as online documentation. There's even an Eclipse plugin, so one day we could collaboratively work on a high-quality documentation using Eclipse and the Subversion repository.
DokBook is another option, but I've got no experience with it.
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Re: Hierarchical modeling

Postby dcuny » Sat Jan 19, 2008 10:51 pm

One of the things that makes AoI particularly nice is their manual. It's maintained in HTML format by a single user.

I think having community maintained documentation would probably be easiest, so Wiki's got an advantage there. So if you can write a perl script to scrape through the pages, that would be great.
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Re: Hierarchical modeling

Postby sascha » Sat Jan 19, 2008 11:32 pm

I think having community maintained documentation would probably be easiest

I agree. I'm not the best person to write the docs for two reasons: I'm the developer, so things obvious to me perhaps aren't obvious to users (and vice versa), and I'm not a native English speaker. So let's stick to this Wiki approach for the time being, and once we've got a useful documentation I can translate it to LaTeX and make a nice PDF - I guess some people still prefer printed manuals to HTML.
Once Jpatch 1.0 is done I'd also like to have a few video tutorials. It's just so much more convenient to watch someone using a software and explaining some features than reading manuals or tutorials.
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Re: Hierarchical modeling

Postby dcuny » Sat Jan 19, 2008 11:58 pm

I'll be happy to work on documentation (being a native English speaker and all that ;)). I'd also like to try some video documentation at some point as well.
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Re: Hierarchical modeling

Postby sascha » Sun Jan 20, 2008 9:54 am

We're drifting off topic here, but anyway:
Do you know which software to use to create video tutorials? I did some research on that topic a few month ago, but all I've found was [url=Virtual Network Computing]VNC[/url]: you basically start a VNC server and run JPatch inside the VNC session. The session can be recorded, and then converted to e.g. mpg-4 with mplayer/mencoder.
I haven't tried it with JPatch yet, chances are that GL hardware acceleration won't work, so I don't know how practical this is.
Any other ideas/expirences?
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Re: Hierarchical modeling

Postby dcuny » Sun Jan 20, 2008 12:09 pm

sascha wrote:Do you know which software to use to create video tutorials?

I've used Wink before. It captures screenshots as frames, and allows them to be played back as Flash animations. You can annotate them, and attach audio to them. It's not as slick as "real" video capture, but I think there are advantages to using it - you can go back the screenshots and edit the annotations, which is less easy to do with video capture.

Here is a demo I did to show off some of the features of the LionSnake modeler I liked. You can adjust the playback timing, and even add some branching, so the users can skip topics if they want. I found it was pretty easy to use, and it runs under Windows and Linux.

Not "real" video, but it's very slick.
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