Page 1 of 1

shapes key mouvement algorithm

Posted: Thu Aug 09, 2007 5:54 pm
by kyes
Hi to all,
How the Blender calculate the mouvement between tow shapes keys.
For exemple:
Basic shape key is a line with 2 vertex
. (V1)
|
|
|
. (V2)

Key 1 : rotate one vertex 180°
. (V2)
|
|
|
. (V1)


In Object mode :
key 1 at 0.5 the two vertex V1 and V2 are collapsed
. (V1,V2)

needed shape is :
._____.
(v1) (v2)

thanks for all
:wink:
K

Posted: Fri Aug 10, 2007 1:16 am
by aligorith
Shapekeys have no concept of rotation or scaling. The only information they store is a location for each vertex at each point. These locations are then linearly interpolated to go from one key to another.

Therefore, the following would happen:

Shape 1:
(v1) (v2)


Shape 2:
(v2) (v1)


If shape 1 is at full influence on frame 1, and shape 2 is on full influence in frame 11, then:
Frame 1:
(v1) (v2)

Frame 3:
(v1) (v2)

Frame 9:
(v2) (v1)

Frame 11:
(v2) (v1)


Sure, there's room for improvement, but storing 'transforms' applied to vertices for each shapekey is not one of them.


In order to get the shape you require, consider adding a third shapekey for that position.

Regards,
Aligorith

thanks

Posted: Fri Aug 10, 2007 11:09 am
by kyes
great
thanks for info
I hope in future version of Blender we can manipulate non linear interpolation between shapes.
:)

K

Posted: Sat Aug 11, 2007 11:54 am
by LetterRip
Shouldn't we be using SLERP to interpolate between keys?

LetterRip