Tips and tricks: Offset transformation, morph, etc.

[Pancho]

I just ran into a problem today, although finding a post with a similar problem, but no solution.

So here's my approach:

For a point cloud animation (move polygon islands by particles) I need to offset the effect for each particle. In this case it is a linear interpolation between two position, which is very similar to a morph, scale or anything of that kind.

In order to do this I create an array with the size of the amount of particles present. I then fill this array (transformStartFrame) with a) a random amount and then b) add another integer which depends on the position on the y-axis. Task done in the ice_init tree. This way the transformation starts close to the origin of the mesh and then "moves" upwards.

To trigger the effect I take a current frame node in the ice_eval tree and plug it into a rescale node. The input start is the value of the transformStartFrame array (each particle gets it's value via a select in array node), then I add the length of the transformation to this value and plug it into the input end value. Important is that the rescale node has clamp enabled. Otherwise you won't end up with a value between 0 and 1.

This way the transformation starts at the desired frame and takes as long as the value added to the begin frame indicates.

Hope this helps anybody.

Cheers
Pancho