Third Stage: Grow Simulation
Now lets move on to another great thing for paint effects and the grow simulation. I will create a simple tree; I will use the Oak White stroke. See here the images.
In this sequence I will animate a growing tree, (it's not too realistic because is only for illustration purposes, if you want to created a realistic vegetation growing simulation you will need to research the real process and create a lot of really defined keys for that, but again you can apply this principles I will show for simulating a lot of great effects not only for vegetation simulations, you can combined with particles and create amazing effects), in order to proceed I will explain the Flow Animation section from the stroke. One important thing is that these sections have direct influences over gaps, twists, and textures move.
This defined the speed, in cycles per second and direction for gaps, twists, and textures moves, and controls the speed that the tubes grow. You can use negative numbers to inverse the movement.
This moves the texture down the tubes.
If you want this option to work, Time Clip must be on. This option will let you animate the tube growth and flow from the beginning of the growth simulation to the end of the growth simulation.
Using Stroke time on, the animated tubes first appear and begin to flow at the time set by Start Time, and die at the time set by End Time.
If Time Clip is on, but Stroke Time isn't, tubes along the stroke path are already planted, which means the tube growth is uniform.
Also define when the tubes appear or born during the grow simulation and when they die. (Start time, end time).
this indicates when the tubes appear, but is set in seconds, so if you are working in 24 frames per second and set the start time to 1, the strokes appear in the 24th frame, you can use decimals to set the right number.
This option defines when the tubes disappear, again is set in seconds, and if you are working with growing simulations try to set this number really high, so you don't get the tubes starting to disappear when your animation is not finished.
Use this option to key frame time. For example, if you are animating the growth of a tree, you can make the tree remain a sapling for the first 100 frames of the animation, then have the tree grow from a sapling to a full grown tree in the next 100 frames.
Now that we know what every option does, let's animate the tree:
For this animation I will make it a little more interesting, I will animate the grow simulation, I will animate and the way the tubes grow, and I will use some wind forces too. So let's start.
First I will animate the grow simulation, by setting the stroke time and time clip on, and the texture flow off, this is because I don't want to animate the texture of my tree, I will set my speed to 0.6, and I will set my start time to 0, so my animation starts in frame 1, and set my end time to a really high number, because I don't want my tree to disappear in this animation.
And believe it or not, that's it, now my tree will grow, of course its not going to be an excellent animation we have almost no control of anything, so I will set my control keys to the tree so the leaves will be really small when they born, and the branches will be very thin, and the width of my tree will be really thin in the beginning and at the end it will be a really big one. Now the question is how I will do that, and it's really easy don't start to panic, you only have to set the keys for the settings you want to correct in the creation section, see some of my values here.
For a real animation I will probably set more keys in more values, so I can control the entire behavior of my animation, and for each value I will set deferent keys in a lot of different values.
See these keys in my graph editor here; I have set keys for, the split range, and angles