Talk:Blender 3D: Noob to Pro/Basic Animation/Bounce

RE: Time to animate!:FRAME 12

If you go into edit mode to shrink the ball then the ball retains the deformation throughout the animation cycle. Perform lattice deformations in object mode for results.

--- Andy,

"With the lattice selected you will want to go into edit mode."

Are you sure that isn't Object mode?

I tried it in both 2.41 and CVS and both say 'Unable to perform function in Edit Mode' when I try to change the U/V/W settings.

--Mstram 08:45, 22 June 2006 (UTC)

''"It is important to add the objects in top view to keep their Z-Axis aligned upwards." '' Hmm, I added a sphere in every view (top,left,right ...etc) and even with a randomly rotated view, the Z axis always pointed in the same direction.

--- --Mstram 09:02, 22 June 2006 (UTC)

"Right click your Ball and go into edit mode."

It didn't seem to matter if I was in Edit or Object mode when I added the Lattice Modifier

--Mstram 09:02, 22 June 2006 (UTC)

In version 2.4x you can select the object (the sphere) and apply a Lattice Modifier to it or you can still use the parent option then use the Modifier palette to make the Lattice Deform "Real" (In my version of Blender, I have to use the second option as the first simply doesn't work :

(Only) applying a lattice modifier doesn't do anything in 2.41 or CVS. I needed to CTRL-P (lattice deform). Does the Lattice Modifier even do anything ?

--Mstram 10:07, 22 June 2006 (UTC)

Yeah, thanks Mstram. It appears a couple of people added edits that were either poorly worded or unnecessary. As clearly stated in my original text, the Lattice modifier does not work the way we need it to work for this tutorial. I've edited the text to make it clearer what we're doing. Someone apparently felt it was worth re-mentioning it anyway. My original text also stated that if the Lattice information wasn't clear, then the reader should learn the lattice basics anyway. I did this because I didn't want to delve deep into lattice principles.

For the same reason, I ignored the U,V,W settings as frankly, they just aren't needed for this exercise. We're not going to twist the ball or kick it with a boot. It's only squashing (and later stretching). I know it works as originally written because I've got a fully working animation done this way.

On the Z-Axis orientation issue, what you'll find if you add objects in different views is that their local axes will be out of whack. This may go un-noticed until you start creating IPO channels manually (try it with a SizeZ IPO for example... SizeZ Channel - CTRL-LMB in IPO window). Then it becomes a problem. "CTRL-A" doesn't appear to solve this problem with Lattices as it does with Meshes.

Anyway, thanks for pointing this out. I've re-edited so hopefully the rest is okay. PLEEEEASE let me know if you find more problems. You know where to find me :) --AndyD 13:04, 22 June 2006 (UTC)

--- Hi Andy, just tried the lattice modifier in 2.42Rc2, and it doesn't work following the instructions in your tutorial. According to your tutorial the lattice is moved/deformed in OBJECT mode, right ? When I add a lattice modifier in any version of blender from 2.41 -> 2.42RC2 / CVS, the lattice only affects the sphere when in EDIT mode, and only with a Lattice type key frame.

.. Also I'd love to see more info on rotating the squashed sphere, and how a lattice makes it easier to do. I presume you mean that the sphere rotates, while the squashed flat part remains in contact with the ground? Have you done this? ... I'm experimentating with that now.

Mike --Mstram 13:55, 27 June 2006 (UTC) --

Thans Mike. I've re-worded the entire section on applying the lattice. Hopefully it works as expected now... for everyone. --AndyD 17:26, 29 June 2006 (UTC)

Not for everyone :) Tried this in 2.44 and had same problems as Mike. Lattice didn't animate as well. --Harkonnen2. 19.08.2007

Comment
Nice work! Things that could be explained a bit better:

Arcs and timing: This is more important then squash and stretch. http://www.exploratorium.edu/sports/ball_bounces/index.html Notice how gravity speeds the ball down, (greater spacing between fames when going faster) then immediately after impact, the ball comes back up at nearly the down velocity, then slows down as it's overtaken by gravity again... Balls do not slow before hitting a surface as currently shown. You have the major keys right, but a little more work in the graph editor is needed.

Squash and stretch: Squash and stretch is rarely seen in real bouncing balls, but we exaggerate this for animation. Stretch helps prevent the strobing due to finite frame sampling in tv and film... If our eyes opened and closed 24/30 fps everything would be strobing... We prevent that by adding motion blur (longer exposure time) or stretching objects as they're moving across the screen.

Currently the article focuses on the Blender technical how-to. More exploration into the simple physics, or at least links to articles that do would make this complete. Suggestions: http://www.idleworm.com/how/anm/01b/bball.shtml http://www.exploratorium.edu/baseball/bouncing_balls.html

For a simple ball bounce like you are doing, I'd parent the ball to an empty instead of using a lattice. The empty can be moved, squashed, and stretched while the ball itself is only rotated. Lattices are nice when you need the ball to warp, dent in the side etc... but is rarely needed for a simple realistic ball bounce and rotations. If you're going to expand this exercise more then the lattice is fine.

--AddZero 20:47, 26 February 2007 (UTC)


 * Thanks for the comments. You're correct that this was more of an introductory Blender "how to" than an investigation of physics or animation but your points are well made. Although I will say the curve editor shows the speed of the centre point of the ball and as such, the bottom curvature and central-bottom key reflects the slowing of the centre-point AFTER contact, during squash and before recoil rather than the air speed of the ball itself. Could the curve be a little more exponential? Maybe but it's a pretty short distance being covered in the example.


 * The lattice is a personal preference and admittedly almost anything could be used as the controller since for this exercise it really is nothing more than a parent object. I find empties hard to see once you have a few objects, lamps, camera and other stuff happening in a scene while a lattice is easy to see and recognise and can also be sized to the dimension of the ball and gives a better visual indication of the state of squash and stretch at any point (imho).


 * I've added the idleworm link to the page as it looks like a very useful resource. Thanks again and, as with any wiki, feel free to rework bits that you feel strongly about. --AndyD 16:48, 27 March 2007 (UTC)

NOTES TO EDITORS
I have added notes within the wiki text explaining why some information was not added to the text. See the comment above for more info. --AndyD 17:21, 24 June 2006 (UTC)