modeling a spring for animation?

[7immy]

Hi
I'm working on an animation (see purple attachment). The object in the middle will eventually be a rocking childerns park thing (see attachment).

I'm currently having trouble with the spring part iv currently got an animated curve on a tube but was hoping i could change this to a spring.

I have looked on the forum's for help and tried downloading the video tutorial on it but it didn't work for me. i also found tutorials that only worked for single renders.

can anyone guide me to a post I've missed or help me out?

thanks for your time.

[Enzoblue]

Quick Tute!

In front view add a mesh circle. In edit mode, select all and hit G then X and move the circle to the left 3 big grid units. Now select the top vertex and the bottom vertex and hit Shift D, then immediately hit X and move the 2 verticies back to the middle. Hit F to connect the two verts then grab the bottom vertice and hit Z and move it down 2 big grid units. Now go into edit buttons, in the mesh tools set Degr to 360, steps to 28 or more and turns to 3 or 4. Select all and hit Screw.

Hit undo and try again if you don't have the right result. Moving the bottom vert of the two in the middle makes your screw spacing longer - moving the circle to the left more makes it wider. You can also change the size of the circle to make it thicker. Experiment. After you have that, select the extra verts in the middle and delete them, then select all and hit Set Smooth.

Now that it's all done, go out of edit mode and back in front view add a Path. Rotate the path 90 degrees clockwise and scale it's length to match your spring. In Object mode select the Spring, then the Path and hit Cntrl+P and select Curve Deform.

Edit: tip here, if you get turned around and your spring is perpendicular to your path, select the spring and in Object buttons (F7) mess with the tracking, hit track X, Y or Z etc and one of them will fix it.

With path selected, in Edit buttons hit Curve Stretch. Open up the IPO editor, change where it says Object to Path, then go to Curve/Extend Mode and select Extrapolation.

Now you can move the control points of the Path in edit mode and it'll flex your spring around nicely.

Hope this helps!

[7immy]

hi Enzoblue thank you so much for your detailed tutorial i now have a spring . Was a lot of help.

But i still cant work out how to animate my path so it bends side to side (like an upside down pendulum) i can only at the moment get it to stretch and compress on the paths axis using the IPO editor.

any chance you could tell me how to do that?

thanks again

[Gimble]

Just a small point on using the Screw function to model the spring:

- the 'Degree:' setting is only used with the Spin and Spin Dup functions; it has no effect on the 'Screw' function. (Just try changing it...)

Another technique, maybe more work, would be to use the Array modifier in combination with the Curve modifier. This doesn't squash the spring like many other approaches.
You can find some examples here (refer to the 'tentacle' example):
http://wiki.blender.org/index.php/Re...s243/Modifiers

Also, here's a quick example file (could use a lot more tweaking of the Relative IPO keys to get a proper recoil, etc):

http://users.xplornet.com/~gimble/spring.blend

[Enzoblue]

Ya, forgot about animating, heh... Instead of using a curve to deform your mesh, use armatures. They really don't take long to learn and you'll be glad you did. I'll give a simplistic quick tute for ya, but for a more complete know how, visit here:
BSoD/Introduction to Character Animation

First place your cursor at the bottom middle of your spring. Hit spacebar/Add/Armature. Hit G and move that bone up a bit, then hit E and extrude up some and keep going until you have 3 or 4 bones.

Now tab out, select your spring then select your armature and hit Cntrl+P and select armature, then select Create From Closest Bones. With your armature selected, hit cntrl tab to enter Pose Mode and look in your edit buttons(F9). In the Display Options hit Envelope. Select a bone with a right click and in the Selected Bones area, change the Dist until the selected bones envelope covers the width of the spring. Repeat with the other bones.

Now for animating. In Pose mode, alternately select the bones and hit G or R and set them so your spring is flexing to the right, then select all the bones with A and hit I and pick LocRot. Advance a few frames with one click on your up arrow key, select bones again and use G and R to set them up to where your spring is bending to the left, then select All and hit I and pick LocRot again. Go back to first frame and hit Alt+A and enjoy.

Now split your screen and change one to the NLA Editor. You can see the diamonds that represent what frame your bones changed. With the Action strip selected, hit C and convert it to an NLA strip.

Now to tune, first click on the little guy that's next to the word Armature, (yes, he's a button), then with the strip selected in the graph, hit N. Now change the repeat to 3. See the number that says Action End? Multiply that by 3 and put that number into the Strip End just above that. Now your action will repeat 3 times at the same speed. Adjust as necessary. You can also select the Action Strip on the graph and hit S to scale it to make the action slower or faster, and you can hit G to grab it and move the action to the frame you want it in.

Whew. This is fun huh? Ask if any troubles.

Check out the above link for the Action Editor and NLA editor to learn more, it's a bit involved.


Edit: Thanks for that Gimble, neat stuff I can learn.

[Enzoblue]

I tried it out Gimble and it's pretty cool. For the spring though, I ran into the problem of animating the spring curve. When it's a coil like that, it's pretty tricky to get it to look natural flexing over to one side by moving all those control points - even with the proportional tool. I did try adding another path and using that to deform the spring curve, but that just brought back the deforming and I felt stupid.

And can you explain how to add the shape ipo's ? I did it by trial and error, but it makes little sense.


7immy! Your website rocks. Small request: get a better resolution/codec for your claymation video clip please, looks neat but it's all cubified.

[Gimble]

I was working on a rough draft for 7immy. Still just experimenting (especially the first couple of parts in the text file)
Seems to be a bug in the Edges to Curve Python script - messes up the ends of the curves in some cases. (Maybe there's some other way to easily create a spiral curve??)
Also needs some refinements for adding ends to the spring; though that's not an issue in 7immy's case since one end is buried in the ground and the other end is hidden as well.
I plan to look into maybe using a lattice to control the spring deformation - might get smoother results than using the Proportional edit tool.

Anyhow, here's what I have now:
http://users.xplornet.com/~gimble/spring.txt
http://users.xplornet.com/~gimble/spring2.blend

[Enzoblue]

Excellent realism there, I like it. I think a lattice would be the same as using a curve though ya? Seems it would be the same fuss just different flavor.

Here's my mini tute on making a perfect spring, (ahem):

In top view add a Nurbs Circle. Hit C to unclose the circle (edit and make it 3D. Find the last control point on one end and select the next point in, so second point from the end. Hit G, Z, then hold control and move it up one grid unit. Go to the next point in and do the same thing, only move it up 2 grid units. Continue around to the last control point, you should be moving that one up 7 units. Now go to front view, select all and hit Shift+D, then Z, hold down Cntrl and move it up 8 grid units. Now select both the last point of the original and the first point of the duplicate and hit F. Now you can duplicate the entire thing again, move it up and double it, whatever you want.

Once you have it long enough, set your cursor at the base, change your pivot point to cursor, hit Z and scale it down. You can also make it wider by hitting S, then X, then Shift Z, (with median point pivot). Do NOT scale it in object mode, it messes up the curves math for some reason.

Beauty.

I did figure out shape keys too Those things are pretty neat.

[7immy]

wow thanks for the suport this is great! i'll give it a try tonight.
thanks

[ecgilboy]

Hey Gimble,

I just stumble in this thread..and I found that spring tutorial & .blend and thats pretty cool..downloaded...