When you are done here, visit my bird avatars and seqs page and my bot page. My e-mail address is mailto:xelag@3dee.com.

The information on this page applies both to 'Lifeforms' style SEQ files, and to the new ActiveWorlds (Hamfon) style text SEQ introduced in AW 3.3. Please note that 'joint' and 'limb' are two names for the same thing.

Contents:

The SEQ File Viewer

SeqFileViewer shows the structure of a binary or a text SEQ animation file. It allows the user to load and save binary and text SEQ files, and to edit a few of their parameters.

File | Open SEQ:
Load a binary or a text SEQ file.
File | Save Binary SEQ:
Save a binary SEQ file. When converting a text file to binary, loss of data can occur (translations, keyframes too near each other).
File | Save Text SEQ:
NEW: Save your SEQ in Hamfon's text format (see below).
Edit | Invert Sign of Quat X & Z:
This option is used for seq files produced by LifeForms for VRML models. These models, as handled by LifeForms, produce seq files with reversed angles around the X and Z (horizontal) axes. For instance, a knee will bend backwards instead of forwards. By inverting the sign of the X and Z elements of the quaternions, this problem is fixed.
Edit | Rename Joint:
Allows the user to change the name of the joints.
Edit | Delete Joint:
Removes the joint definition from the seq file. Useful if you only need to animate certain joints. For instance, qwave.seq animates the back and 3 other joints, and can be used during the wait animation without interrupting it: only the arm will move differently. Another example is given by VRML animated models: these carry an extra joint, without a name, that is parent to the pelvis. You can delete it from the seq file.
Edit | Rename Root Joint:
Allows the user to correct the name of the root joint, which for ActiveWorlds animations should be 'pelvis' (although ActiveWorlds doesn't seem to care what the root joint is called in the seq file).
Edit | Rescale distances:
The positioning of the pelvis can be rescaled.
Edit | Set First Frame:
The pelvis positioning on the first keyframe can be fixed for binary files.

Download the SeqFileViewer 2.2 to view (as text) and edit the information in a binary or text seq file.

The two SEQ file formats

Traditionally there was only one format for SEQ files: the so called 'Lifeforms' binary SEQ file.

With the appearance of Active Worlds 3.3, Nelson Crowle (HamFon) introduced a text format, which allows more flexibility: all 'joints' (there called 'limbs') can be displaced as well as rotated, and there are provisions for rescaling them too (not yet implemented in 3.3 or 3.4).

The binary SEQ file format

Active Worlds only uses part of the information in this SEQ file to animate avatars. The root joint is usually mentioned twice, in the header and in the Rotations section. It does not seem to matter to AW if it is left blank in the header (AW will use the 'pelvis'), and it may be omitted in the Rotations section if it is not needed. For example, qwave.seq specifies a root joint 'pelvis', but only defines data for back, lfshoulder, lfelbow and lfwrist. Some Seq files have an anomaly: the Model is called 'pelvis', the root joint is left blank (gray01.seq and others). The Location data (groups 1 to 3) refer to this root object and should normally be 0, 0, 0 for the first frame: units represent metres as experienced in Active Worlds. Facing is ignored, the Rotation quaternions for the pelvis (if present) are used to regulate facing. The last groups marked unknown are probably ignored as well.

The names of the joints are important: Active Worlds will ignore all data which refers to joint names it does not recognise. The hierarchy is undefined in the SEQ file because it is already defined in the RWX file, so tags may be applied to any joint (clump) in any order (except for the pelvis, which is always the root), but are usually applied using the humanoid model. The standard tag numbers (used in the RWX file), joint names (used in the seq file) and description for a humanoid avatar are:

tag number in RWX clump	joint/limb name in SEQ	description and function in a normal humanoid avatar
1	pelvis	this is the root joint
2	back	torso, child of pelvis
3	neck	child of back
4	head	child of neck (or of neck2 if used)
5	rtsternum	right sternum, child of back, often omitted
6	rtshoulder	right upper arm, child of rtsternum (or of back if rtsternum is missing)
7	rtelbow	right lower arm, child of rtshoulder
8	rtwrist	right hand, child of rtelbow
9	rtfingers	right fingers, child of rtwrist, usually absent
10	lfsternum	left sternum, child of back, often omitted
11	lfshoulder	left upper arm, child of lfsternum (or of back if lfsternum is missing)
12	lfelbow	left lower arm, child of lfshoulder
13	lfwrist	left hand, child of lfelbow
14	lffingers	left fingers, child of lfwrist, usually absent
15	rthip	right upper leg, child of pelvis
16	rtknee	right lower leg, child of rthip
17	rtankle	right foot, child of rtknee
18	rttoes	right toes, child of rtankle, often omitted
19	lfhip	left upper leg, child of pelvis
20	lfknee	left lower leg, child of lfhip
21	lfankle	left foot, child of lfknee
22	lftoes	left toes, child of lfankle, often omitted
23	neck2	the neck can be hinged using this tag as child of neck: in this case the head is a child of neck2
24	tail	optional, child of pelvis
25	tail2	optional, can be attached to tail
26	tail3	optional, can be attached tail2
27	tail4	optional, can be attached tail3
28	obj1	optional prop, child of any other
29	obj2	optional prop, child of any other
30	obj3	optional prop, child of any other
the following 12 tags were introduced in AW 3.3, but they were not working properly for text SEQs. As from AW 3.4 (browser 494 or 495?) they work both for binary as for text SEQs.
31	hair
32	hair2
33	hair3
34	hair4
35	rtbreast
36	lfbreast
37	rteye
38	lfeye
39	lips
40	nose
41	rtear
42	lfear

All numeric formats in the SEQ file are bigendian (Macintosh), to read them on Intel machines reverse the order of the bytes. Locations (positioning) are relative to the resting position of the Pelvis (root joint), rotations are relative to the resting rotation of the joints. Frame numbers start by 1 (not 0).

# of bytes	format	description
Header
4	integer	header, 7F7F7F79 and 7F7F7F7A
2	integer	total number of frames, includes key frames (mapped in the seq) and all others, i.e. is the number of the last frame.
4	integer	number of joints. NJoints
2	integer	length of next string, including trailing nul-byte. x
x	string	name of model + nul-byte
2	integer	length of next string, including trailing nul-byte. y
y	string	name of root-joint, including trailing nul-byte.
The Rotations of joints are defined as quaternions in specific frames. Intermediate frames are interpolated by the renderer.
Joints loop (1st loop), NJoint times
2	integer	length of next string, including trailing nul-byte. x
x	string	name of joint, including trailing nul-byte. In the first iteration, is usually the name of the root-joint (same as previous string)
4	integer	data length in each iteration: 16 bytes, corresponds to 4 * 4 bytes of the quaternion floats
4	integer	number of frames in which this joint has quaternions defined. NFrame
Inner Frame loop (inside Joints loop), NFrame times
4	integer	frame number
4	float	data: Rotation Quaternion of joint. Quaternion W
4	float	data: Quaternion X
4	float	data: Quaternion Y
4	float	data: Quaternion Z
End of Inner Frame loop
End of Joints loop
Next, there are a variable number of blocks of frame loops. For example, the dredd03.seq has 9 blocks: blocks 1 to 3 indicate the position of the model in metres from the origin of the scene (not in Dekametres, as are used in the RWX and world units), block 4 has a rotation Quaternion (Facing), blocks 5 to 8 have each a 4-byte data field, block 9 has a rotation Quaternion. The first 3 (or 4?) are probably mandatory for ActiveWorlds. I have counted up to 9 blocks (dredd03.seq). Note that very few files omit these blocks altogether: typically the 'wave' animations. These anomalous SEQ files crash LifeForms, but Accutrans 3D (from version 6.32) accepts them. If the blocks are not omitted, they must contain at least one set defining the X, Y, Z Location for frame number 1, otherwise the positioning of the avatar in animation is random.
4	integer	number of blocks of information: variable
Block 1: Location X
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Location X Loop, f times
4	integer	frame number
4	float	data: Location X
End of Loop
Block 2: Location Y
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Location Y Loop, f times
4	integer	frame number
4	float	data: Location Y
End of Loop
Block 3: Location Z
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Location Z Loop, f times
4	integer	frame number
4	float	data: Location Z
End of Loop
The rest of the file is not used by Active Worlds
Block 4: Facing
4	integer	data length: 16 bytes, = 4 bytes * 4 floats
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: Orientation Quaternion of model (not used in AW?). Quaternion W
4	float	data: Quaternion X
4	float	data: Quaternion Y
4	float	data: Quaternion Z
End of Loop
Block 5: unknown
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: unknown
End of Loop
Block 6: unknown
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: unknown
End of Loop
Block 7: unknown
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: unknown
End of Loop
Block 8: unknown
4	integer	data length: 4 bytes (float)
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: unknown
End of Loop
Block 9: unknown quaternion
4	integer	data length: 16 bytes, = 4 bytes * 4 floats
4	integer	number of frames in the block. f
Loop, f times
4	integer	frame number
4	float	data: unknown Quaternion W
4	float	data: unknown Quaternion X
4	float	data: unknown Quaternion Y
4	float	data: unknown Quaternion Z
End of Loop
End of file

The text SEQ file format

This format was introduced by HamFon (Nelson Crowle) in AW 3.3. It is an ASCII file, that can be edited with any text editor (for example, Notepad). It consists of lines of text, each line ending in a carriage-return + line-feed pair, as is usual in Windows ASCII texts. It contains similar but not identical information to the binary format. In fact, it allows translations of 'limbs' (in binary format called 'joints'), as well as the traditional rotations. The format also allows information for scaling, but this has not been implemented (yet) by Active Worlds (scaling information, if present, is ignored).

See example below. The first line contains a magic word AWSQ, the version number Version=1, the number of limbs Limbs=7, and the duration in milliseconds Duration=4633. Next follow the limb sections (7 in this case), each with its own header (shown in bold here). The limb header has the limb name and the number of frames. Within a limb section, each line represents a frame (or keyframe): first number (integer) is the time in milliseconds, next four numbers (in blue here) represent the rotation in axis-angle notation (x, y, z, angle in degrees), the next three numbers are the xyz translations (in AW coordinates or decametres). Three more numbers may follow for xyz scaling: 1.0 1.0 1.0 is default (this is optional and is not yet implemented by AW, and is not shown in this example).

AWSQ Version=1 Limbs=7 Duration=4633
pelvis frames=4
0 0.000000 0.000000 1.000000 0.0000 0.0153 0.0000 -0.0043
1700 0.000000 0.000000 1.000000 0.0000 0.0153 0.0000 -0.0043
3133 0.005932 0.000000 -0.999982 349.1282 0.0269 -0.0008 -0.0086
4633 0.005932 0.000000 -0.999982 349.1282 0.0269 -0.0008 -0.0086
lfhip frames=4
0 0.036796 -0.028458 -0.998918 353.6962 0.0000 0.0000 0.0000
1700 0.036796 -0.028458 -0.998918 353.6962 0.0000 0.0000 0.0000
3133 -0.226745 0.004188 0.973945 345.7601 0.0000 0.0000 0.0000
4633 -0.226745 0.004188 0.973945 345.7601 0.0000 0.0000 0.0000
lfknee frames=4
0 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
1700 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
3133 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
4633 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
lfankle frames=3
0 0.000000 0.000000 1.000000 356.6163 0.0000 0.0000 0.0000
3000 0.723511 -0.016471 -0.690117 356.2214 0.0000 0.0000 0.0000
4633 0.723511 -0.016471 -0.690117 356.2214 0.0000 0.0000 0.0000
rthip frames=4
0 0.000000 0.000000 1.000000 354.5141 0.0000 0.0000 0.0000
1700 0.000000 0.000000 1.000000 354.5141 0.0000 0.0000 0.0000
3133 0.543298 0.155699 0.824976 332.1506 0.0000 0.0000 0.0000
4633 0.543298 0.155699 0.824976 332.1506 0.0000 0.0000 0.0000
rtknee frames=4
0 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
1700 0.000000 0.000000 1.000000 0.0000 0.0000 0.0000 0.0000
3133 -1.000000 0.000000 0.000000 342.8727 0.0000 0.0000 0.0000
4633 -1.000000 0.000000 0.000000 342.8727 0.0000 0.0000 0.0000
rtankle frames=3
0 0.000000 0.000000 -1.000000 354.2058 0.0000 0.0000 0.0000
3000 0.149576 -0.018882 -0.988570 352.2866 0.0000 0.0000 0.0000
4633 0.149576 -0.018882 -0.988570 352.2866 0.0000 0.0000 0.0000

The format requires that at least TWO frames be defined for each limb. Frame count starts at 0 (milliseconds), this first frame at time 0 must be defined for each limb. The end frame must be within the range specified in the first line of the file (in this case, between 1 and 4633), and must be at time > 0. Not all limbs need to have the same number of frames at the same times.

The limb names are as specified in the binary SEQ section. As from AW 3.4, 12 extra limbs may be used.

Notice that in this example, only the pelvis has translations (like in binary SEQs). But all other limbs can be translated too, if necessary. The order of execution is (I think, I need to confirm this, feedback is welcome): scaling (not used), rotation on own pivot, translation of pivot relative to parent limb.

Empty or comment lines are ignored (but the first line must be the file header). A comment line can start with # or //, other symbols are possible according to Hamfon, not quite clear which.

I have used spaces as separators. According to HamFon, other separators are also valid: TAB, comma, and a few more. I stick to spaces :)

Compatibility between binary and text SEQ formats

Binary SEQs can be fully represented by text SEQs, i.e. you can change a binary SEQ into a text SEQ without loss of information.

Not so from text to binary SEQ. (1) Text SEQs carry information for 1000 frames per second, binary SEQs for 30 frames per second, so some frames may be lost when converting to binary format, and the timing is rounded off to the nearest 1/30th of a second. (2) Text SEQs have information for translations (and scaling) for all limbs, binary SEQs carry only information for the translations of the pelvis.