Something missing from the flower tutorial?

Hi Guys,

I have been playing around with the flower tutorial (, and if I do exactly what the tutorial says, I get the following result: (deleted from youtube)

Unfortunately, it has this ugly circular motion of the right side of the stem in it when the bud starts to grow. I had expected the intended result, would have been something like this: (deleted from youtube)

It appears that the introduction of the dynamic vertices in the bline is not enough to start the smooth growth of the bud and continue the smooth growth of the stem. Or am I missing something?

The way I got my version to work is to have two adjacent frames look exactly alike, but have the first without the dynamic vertices and the next with them. Basically have the first frame be the end point of the first part of the growth (of the stem) and have the next frame one be the start point of the second part of the grow (of the bud).
To get the same shape in the second frame with the dynamic vertices, requires however heavy tweaking of the tangents of the surrounding vertices. Or is this the only way to do it?

Do I make any sense?


This would be easier to understand with the faulty sifz file, I think :slight_smile:
I did this stem part a few times while I was writing the tutorial, and I don’t recall any big problem with the way the edges moved, but maybe I tweaked a few things without even paying attention.

I should redo it I suppose, because right now I completely forgot the context :unamused: so it’s a little hard to understand the problem.
I don’t have the time nor the will right now, but I may try it later today.


I included a red focus box to indicate when and where the oddness occurs.

This might very well be the correct (but unintended) effect of the interpolation
(probably more extrapolation) of a dynamic vertex. And that I simply need to
add some extra vertices to guide the stem.

I just don’t know…

flower.sifz (3.44 KB)

This problem was also visible in “examples/star.sifz”.
The problem was originally introduced in revision 1150.
Fixed by dooglus in revision 2149.