• 28May
    Projects, Uncategorized Comments Off

    Comparison of Blender and SL poses

    A new revision (2008-05-28) of the Blender to BVH exporter is available. Here are the noteworthy changes:

    • Added GPL2 as licensing option.
    • Added hand and foot control bones (scale 1.5 to enable).
    • Bone adjustments to make Auto-IK work better.
    • Auto-IK enabled by default.
    • Minor skeleton tweaks in the knees.

    A note about Auto-IK: for this revision, Auto-IK is enabled already, to make it easier for beginners to pose the armature. Just grab and pull on the arms or legs (but not the hands or feet; those won’t work), and the limb will move around. If you don’t want Auto-IK, click off the “Auto IK” button in the panel on the right (about 1/3 of the way down the screen).

    A note about the hand and foot control bones: by default, they have no effect. But if you scale them up to scale 1.5 (select the bone, press S, type 1.5, press enter), the corresponding limb will try to reach for the control bone, using IK. You can use this to keep the feet planted on the ground, for example. If you don’t want the control bones cluttering things up, you can hide them by selecting them and pressing H; get them back with Alt-H.

    By the way, a tip about using IK targets (like the control bones): it works best if the limb is already (without IK) in a pose similar to how you want it. So, IK just gives it that extra “snap” to keep it in place. If you only use IK without posing first, the limb might bend the wrong way and you’ll have to see a doctor.


    P.S. This doesn’t mean I’m maintaining it… :P

  • 19May

    Long-time readers may recall my post last December about an animation exporter project I had been working on. I’ve been meaning to release it to the public for a long time now, but never got around to it… until today!

    I’ve cleaned up the script and packaged it in a Blend file with the skeleton (it can’t export arbitrary skeletons as animations, it’s currently tailored to a specific one). The download link is below, but first I’m going to make you read my statement:

    This script is the product of countless hours of study, effort,and tweaking. I had intended to use it myself to create and sell animations in Second Life, but plans and interests change, and I don’t see myself doing that anymore.

    So, rather than keep it to myself, or let it linger untouched on my hard drive until the heat-death of the universe, I’ve decided to release it for the benefit of other animators and the general public. I hope some people find it it useful, and it makes their lives a little bit easier.

    But, I have no interest in maintaining or providing support for it. So, if you can’t figure out how to use it, find someone else to teach you. If it stops working, find someone else to fix it. If you need it to do something new, find someone else to improve it.

    I’m not trying to be rude. I’m sure you’re a very nice person. But I have a lot of ideas, and not a lot of time to spend on things that don’t interest me anymore.

    That said, if you have the inclination to write me and say thank-you, or tell me about a project that it has helped you with, that would make my day. (I’m jacek.antonelli on gmail.)

    - Jacek Antonelli
    (May 19, 2008)

    So there you have it. Go free, little exporter! Go free!

    [Update Dec 15: PLEASE NOTE: If you get an error about a missing pickle, you will need to install Python.]

    Both the scene file and the script are distributed under the Creative Commons Attribution 3.0 United States License. (As is the image up top.)


    [Update: If you wish to use Blender's Auto-IK feature for posing, you will need to unlock the left hand's location. To do this, select the skeleton's left hand, press N to open up the Transform Properties, and turn off the little lock-shaped buttons next to LocX, LocY, and LocZ. You may wish to do this for other bones as well, depending on your needs.]

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  • 04Jan

    Attention, readers: I’m looking for an enterprising geek to OGLE my avatar — that is, to capture the 3D mesh of my avatar shape.

    I will pay L$ or USD$ for a mesh capture of my avatar. I have the following modest requirements:

    1. The final result must be in Wavefront OBJ format.
    2. Will pay extra if it has UV texture coordinates intact.
    3. Attachments and skin textures not needed.

    If you can do this for me, please leave a comment, IM in-world (Jacek Antonelli), or email (jacek.antonelli ~ gmail.com).

    [Update: The ever-cutetastic Patchouli Woollahra very kindly OGLE'd my avatar. Thanks, Patchi!]

  • 17Dec

    Update: Check out my animation exporter download and tutorial.

    Back in May of this year, I posted about my work on a script to export animations from Blender to SL-compatible BVH files. Well, as you can see from the comparison screenshot below (click to enlarge), I’ve made a lot of progress since then.

    Comparing the animation played in SL (left) with the animation as it appears in Blender (right)

    (Mind you there’s some difference between the camera angle in the two shots, and possibly some slight mis-rotation of the hands from SL’s rather zealous animation ‘optimizing’ algorithm.)

    Some difficulties I’ve encountered:

    • As mentioned in my earlier post, the axes of rotation for the bones in the SL skeleton differ from the Blender skeleton. That is, in the Blender skeleton, the Y axis always points along the length of the bone. In the SL skeleton, it varies between bones.
    • Furthermore, the order of rotation for the Euler angles varies from bone to bone in the SL skeleton. I have had to employ code to convert from one order to another to correct for this. It seems to have done the trick.
    • SL has a bug which duplicates the first frame of an animation. (VWR-3783)
    • Using IK on the Blender skeleton, especially in the legs, tends to cause jittering in the SL skeleton — that is, wobbly knees and ankles. My best guess at the moment as to the cause of this is SL’s insistence on converting all joint angles to integer degrees. Subtlety, be banished!
    • Certain rotations result in a significant difference in the appearance of the animation. I’m pinning the blame for this one on Gimbal Lock. That’s right, I’m looking at you, Mr. Lock.

    Nevertheless, my animation exporter script is a very significant step up from Qavimator: smooth blending between keyframes (controlled by my most-beloved BĂ©zier curves); custom rigs for different types of animations; inverse kinematics to provide that extra stick in the feet; layering and blending single actions to create longer animations; and all the rest.

    And as it happens, I’m currently in a trial period as animator for one ChronoForge 4D, a manufacturer and purveyor of sharp, pointy things with which to poke and jab at other similarly-minded avatars. So next time you stab someone through the heart and then kick their body to the ground (in SL), you might say a little thanks to the kindly, peace-loving artist who made it all possible.

  • 20Aug

    Tentacolor Preview

    Funny how the tiniest little remarks can inspire the most interesting ideas. I was chatting with Chrysocolla Rau in SL yesterday, and the conversation turned to the topic of tentacles, as conversations with me are wont to do.

    Chrysocolla (perhaps prompted by my last name, Antonelli) mused that the Italian word for ‘tentacle’ is probably quite wonderful. Despite my name, I am neither Italian nor fluent in the language, so I looked up the translation: tentacolo (pl. tentacoli).

    One tiny mental connection later, the concept of “Tentacolor” was born! I worked feverishly lazily into the night to produce something to show this remarkable Tentacolor. The image above is one frame out of a psychodelic, hypnotic, tentacolored animation. When finished, I’ll put the movie up on YouTube or similar, for the enjoyment of all!

  • 25Jun

    “Edit Linked Parts” Menu Item (new in!)

    You might notice a new entry in the Tools menu for SL Edit Linked Parts!

    That’s right, the feature I added back in March and submitted to the JIRA has now made its way into the official client release! The menu item works just like the checkbox in the Build/Edit floater, allowing you to switch between editing whole linked sets of prims, or editing the individual members.

    Not good enough? You want more?

    Well then how about I tell you guys how you can add your very own keyboard shortcut… in just 3 easy steps?

    1. Open the Second Life/skins/xui/en-us/menu_viewer.xml file in your favorite text or XML editor.
    2. Go down to line 695 (or do a search for “Edit Linked Parts”) where it says shortcut="", and type in your shortcut between the quotation marks! For example, to bind it to Shift-L, you’d type in shift|L!
    3. (Re)start Second Life, and enjoy!

    A word about the format for shortcuts: Put the modifier keys first, separated by the pipe character, | (Shift-Backslash, above the Enter key). The standard order for modifiers is control|alt|shift, but I’m not sure the order matters too much. For Macs, “control” means the Command key.


  • 04May

    Over the past week, I’ve been working on a script to export SL-compatible BVH animations from Blender armatures/sketelons.
    Continue reading »

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Recent Comments

  • The feet and hand control bones can be used for inverse kine...
  • thanks! It's woahking! However I have a problem...someho...
  • it is very nice.i can easly understood for animation work.th...
  • I just want to thank you very much!...
  • Sorry, the exporter only works with Blender 2.49 and earlier...