• parameter morphing issue

Hi again,

I'm trying to find out, how I can morph between a fix value "X" and 4 different values "Y(1,2,3,4)", if "Y" is also morphing between it's four values at the same time!
I don't want Y(1,2,3,4) to be the 4 scenes on an x-y-plane!
I want it more the way that these 4 values can be mixed using 4 faders to result in a weighted average, but I cannot imagine how to get this done...

Any ideas, you guys?

• Posts 16 | Views 6319
• @elden You could try the pd/extra/pmpd folder. It contains some weird (and sometimes very useful) stuff like [iSeg2D].........or maybe [iAmbient2D].......
Maybe [Mass3D] or one of the other objects in that folder? ......
You can use them to move objects around between masses and control how they interact.
David.

• I guess that this physical modeling stuff is not very useful, because what I try to do is relatively static and linear mathematics compared to what pmpd offers.
I think it would be best, if we could find out a certain mathematical formula for my kind of problem anyhow.
Maybe this sketch here can explain it a little better:

My Questions:
-How to calculate the value "X" in dependence on B,C,D,E?
-How to make it a movable value, so that the direction of the morphing path from A to X changes?
-How would X be calculated, if not only 4 values (B,C,D,E) would exist, but maybe 8 for instants?
-How would a change of one or more values (accept for A) affect X?
-Would X stay the same, if the values (B,C,D,E) swap among each other?

• @elden Just so I understand you, is this essentially what you are trying to do but using pd instead? That is, multi-parameter morphing? (Skip to 34:10 if link doesn't take you there)

• Yes, but not like in the video.

The morphing I want to do is not just morphing using an x-y-pad.
It's more like morphing from a certain point "A" towards a movable point "X" on a kind of sailcloth that's clamped between 4 or 8 points like this http://www.lisori-sonnensegel.de/tl_files/lisori_referenz/lisori-sonnensegel-referenz_21.JPG in a coordinate system in which every possible point is a certain sound.

The points B,C,D,E span the sailcloth and A is an outside point. Point X is a movable point on the sailcloth like the point of a laserpointer that hits it. It defines the end-position of the distance A-X that is the morphing path.
Every point represents a parameter set that results in a certain sound and all possible positions X can be, are sharing aspects of all edge-points B,C,D,E in a certain ratio to one another.

I want to know, how this curved sailcloth and the point X on it can be calculated and how to move X around.
Is there a mathematical equation that describes that anyhow?

Sorry, I couldn't exaclty say yesterday, what I try to find out...I haven't been sure how to articulate my thoughts so others understand me.

• If I've understood correctly, then this is what you're after.

morph.zip

Open the "morph.pd" file. The points correspond to those on your diagram, so A and X are the terminals which the slider slides between, and D E C and B are other chosen points. The "point.pd" abstraction calculates the distance between the slider position and the chosen point, using the Pythagorean theorem. You can easily multiply the points.pd abstraction if you want to calculate more than four points.

Apologies if you don't have extended. You can replace the [grid] object with two sliders to make it Vanilla compatible, or just use floats.

• Wow! That looks really useful!
If I wouldn't only have just figured out a problem I didn't see before:
My imagenative sailcloth cannot be compared to a curved plane inside a coordinate system as it's points are higherdimensional in itself (128 MIDI CCs each) !
That's far too complex to realize this idea in a lifetime, I guess...

• Well...
I could anyhow equate every point (B,C,D,E) with a percentage of 25% and then restack the percentage onto the point the "X" shall move to using sliders or something, right? That should automatically set weights to the points. This is the most simple way to solve this I could think of...BUT...I again don't know how!

Help?

• @elden Hello Elden,
I think you should look at PMPD again. You are trying to create a sort of static solar system where all of your points abcdef.....etc. (planets) have "moons" a(x) b(x) c(x) etc. which are the values that you are looking for.
X, a, b, c and a(x) b(x) etc. can have weights (masses) and be attracted (or repelled?). As X (the Sun) moves amongst the planets, the moons a(x) b(x) etc. (...the values that you are looking for?....) are moving because of the "mass" of X amongst them, being drawn from their fixed points abde....etc. towards X, but constrained by elastic string (gravity) connected to their host planets...... (I think, but of course I will be wrong!)
David.

• Wow - great analogy! Never thought about anything like gravity and space curvature to solve this problem! Amazing... and how would you patch this? Is it complex?

• @elden I think you will be cleverer than me at making this happen....
and then in the....... pd\extra\pmpd\examples....... folder you might even find what you are looking for.......
Good luck,
David.

• I'll take a shot at it. Maybe I find out something useful. Thank you!

• @elden WOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
It's the first time that I have looked at the examples........ it's not "processing" but it is Pd on steroids......
many thanks to Cyrille Henry..... WHOO HOO!!!!!!!!!!!!!!!!!!!
Play with.......38_elastique_membrane_on_a_sphere.pd............ and never ever again doubt that it can be "DONE" with Pd............
David.

• @whale-av Holy crap I've been using pd for like 4 years now and have never seen this. Incredible

• Membrane mathematics is what I was looking for! Obviously it's physical modeling. Cannot understand how I could have overseen this! Great!

Posts 16 | Views 6319
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