Thursday, August 9, 2012

Towards Essential Body Relationships

Though I am intending to map the motions of Tofail Ahmed to an abstract visualisation, I want to ensure that important perceptual aspects of the body motion translate effectively. So it is helpful to analyze the performance motions. My intent is to identify high-priority relationships or parameters that I will seek to honour in the abstract visualisation. What "honouring" can and will mean in practice remains to be seen.

Gesture Types

Borrowing terms from Martin Clayton's study of gesture in Khyāl performance (2007), the performances I recorded of Mr Ahmed contained physical gestures that serve as "markers", "illustrators" and "emblems".

Marker gestures indicate a specific time point in musical structure, such as beating a pulse, identifying a downbeat, etc.

Illustrators appear analogous to the melodic flow/motion. The vast majority of the motion falls into this category. It is one vast territory that covers a lot that is very interesting — and very difficult to talk about analytically. This, perhaps, is precisely why it is so valuable!

Emblems, or symbolic gestures, are more based on cultural convention and can be translated relatively readily into a verbal equivalent. An example would be indicating approval with a hand wave.

Emblems would be the most problematic type of gesture given my intent. An emblem is at high risk of disappearing in an abstraction, given the very precise body-arrangement and audience reading it entails. Fortunately, there are very few emblems in the performance I am working with. The closest is an invocation-type emblem. This general position — palms close together, often in front of the face — is important. It creates the impression of focus and preparation, and occurs at the beginning of the first and last phrases of the performance. It also appears at the start of 11 other  phrases of the 60 total phrases. This invocation emblem is also often acting as a marker of the start of phrases. It is doing dual duty.

Invocation: Hand position at start of phrase 1

I am wagering that the element of proximity/closedness is as crucial here as the fact that this can be read as a sign of invocation/gathering.

If the invocation emblem often marks the start of a phrase, the most common marker of a phrase start involves the fingers oriented towards each other horizonally, at mid-body level. The example below is appears at the start of phrase 3:

Rest Position: Hand position at start of phrase 3
I am calling this the rest position. 27 of the 60 phrases start with the hands arranged in this general position. Five others are in closely related positions.

Though there are true full-rest positions of hands on knees (at start) or hands in lap (at end), these seem like outliers that won't be useful as a base position, since none of the Illustrator gestures operate in those spaces.


Given the above clues, I created some measures to help explore what body relationships might be highly correlated to the structure of the music. Basically, I am assuming that if my abstract visualisations at least clearly carry some of large scale articulators of phrasing, the details within will "take care of themselves".

Proximity to Rest Position (PRP): Clayton (2007) used distance of hand from a rest position in his analysis. I am taking a similar approach, measuring the distance from each finger tip to the neutral position and summing those distances. [Aug 10: However, I might consider using a different term, like neutral position, since Clayton appeared to use rest position to apply to true resting of hands on the legs.]

I did this in Blender by creating an Empty at the rest position and an Empty to represent the distance. I animated the Z axis of the latter with a Driver:

Finger Tip Proximity (FP) and Thumb+Finger Tip Proximity (FTP): The finger tips are in close proximity in both the invocation and the neutral position. So it could be of value to simply measure the distance between the finger tips.

Plus, I took a more refined measurement of hand tip proximity is to take the distance between the finger tips and between the thumb tips, and average them.

As it turns out, close finger tip proximity is often closely related to the beginning of phrases. However, finger tip proximity also closes in fairly often during other mid-phrase events.

Shoulder to Hand Proximity (SHP): The close-to-body versus far-from-body contrast also seems important. As the arms straighten, hands move away from the body. So a simply measure of the degrees of far-from-body is the distance between the shoulder and the hand. This measure sums the left and right shoulder-to-wrist distances.

Hand Closedness (HC): This sums the left and right finger-tip to wrist distances, to provide a measure of the open versus closed state of the hand.


The above video shows the first 18 phrases, with graphic representation of the above measures. This is enough to convince me that Proximity to Rest Position is an excellent candidate to focus on. (But how?)

I could spend a lot of time now analyzing the relationships of these measurements to the music. But that probably will not actually help me attain my immediate goals, so I might have to set that aside for another time.


Clayton, M. (2007) "Time, Gesture and Attention in Khyāl Performance". Asian Music v.38 n.2.

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