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View Full Version : 4 cubes, 3 hinges, 2 endomorphs and 1 problem



marke
06-05-2014, 04:26 AM
The problem is the boxes are changing size as they move, I don't want this to happen. Is this do-able with endomorphs or should I be trying IK?

Lightwave 10

hrgiger
06-05-2014, 05:34 AM
You can't do this with endomorphs because they're linear. Which means that all the points in your object are moving in a straight line from the base shape to the morphed shape which is why they are changing scale. So your rotations that you used in creating the morph are turning into point translations.

marke
06-05-2014, 06:51 AM
Thanks for that, do I need to do this as simple forward Kinematics. I t may look simple but it has me puzzled.

Every4thPixel
06-05-2014, 07:12 AM
I wouldn't do this with morphs. It's better to rig it.

marke
06-05-2014, 09:28 AM
Meaning bones, with IK? I am not experienced at rigging and my knowledge on how you would put bones in a solid cube is zero. Thanks for the advice anyway

Danner
06-05-2014, 09:49 AM
I dunno what you are trying to do exactly, but simple mechanical objects all you usually need is good pivot point placement and correct parenting.

jeric_synergy
06-05-2014, 10:07 AM
I think it's a common misconception that IK has to do with Bones exclusively: not true. ANY item, including cameras and lights, can use IK.

Especially for pistons, IK can be used to build mechanical rigs. An entire complicated robot can be rigged using IK and zero Bones.

If you're a beginner, I HIGHLY recommend you avail yourself of Rebel Hill's rigging tutorials on YouTube, on his RHLW channel. Absolutely invaluable, and starting at the VERY basics, which it seems you need to get a handle on. I've used LW >10 years and it was good to have some very fundamental concepts re-visited.

marke
06-06-2014, 09:21 AM
thanks, I am ploughing through these tutorials now

marke
06-06-2014, 09:26 AM
http://vimeo.com/97536384

marke
06-06-2014, 09:44 AM
http://vimeo.com/97536384

- - - Updated - - -

Guess my mov hasn't been working, try this Danner http://vimeo.com/97536384

jeric_synergy
06-06-2014, 09:51 AM
Gotta admit, while the tools we listed will most likely be sufficient, a fair dose of cleverness will probably be required to get it all working.

marke
06-06-2014, 11:07 AM
Thanks for not making me feel like a complete idiot. Each cube is a separate object with a pivot point, do they all look at 1 null goal with IK ? This will not stop them colliding with each other right ?

jeric_synergy
06-06-2014, 01:50 PM
If they are only doing that motion ONCE, treat each pair separately. That's easy: it's just an elbow joint (I think).

I'm not the swiftest with this kinda stuff but: in LW I'd have an invisible "control rod" that is just two points. Think of it as a real world thing: when the points are far apart, the boxes hinge one way, when you draw the points together, they hinge the other way, just like pulling your hand to your shoulder.

Then you mirror the rig to the other side, using the same control points. If you get one side working, the other side HAS to work, no?

To continue with the analogy: imagine you glued one box to your (outer) forearm, and another to your tricep. (Your 'humerus'.) Right?

Remember you can move the pivot points to wherever they make sense. You can build a little 2d version of this with cardboard and brads to see how it would work.

jeric_synergy
06-06-2014, 02:23 PM
Here's one half of your scene: 122207

marke
06-07-2014, 04:08 AM
Hey Jeric that is really cool and clever, the control rod (2points) is what I couldn't think of. I will let you know how it works out, many thanks.

jeric_synergy
06-07-2014, 08:53 AM
Start w/tweaking the pivot points in that sample: they're not quite where they should be. It's all simple fractions of 1meter.

And a good case for making it easy on oneself by using easy dimensions.

BTW, 'faking' this all with Expressions would almost be easier than the IK route.

++++++++++++++++
here's the full meal deal, using IK: 122211

122212

jeric_synergy
06-07-2014, 02:43 PM
Here's the same thing with Motion Controllers: this is probably the simplest to setup.

122216

marke
06-10-2014, 02:53 AM
This motion controller seems to work perfectly but I can't see any controls for any of it. I am on LW 10 when I load the scene I get an error about "No plug-in of type Nodehandler found with name input, would you like to load it from disk ?" I ignore this and scene loads, is this where I am missing something?

Every4thPixel
06-10-2014, 08:38 AM
Here's my 5 cents.
This setup keeps the boxes in the middle and is easy to animate with a slider. Because it's uses IK it's a bit snappy.

122236

Every4thPixel
06-10-2014, 08:55 AM
Just parented it to a Null so you can drag the whole setup around without getting any art effects.

122238

jeric_synergy
06-10-2014, 09:07 AM
This motion controller seems to work perfectly but I can't see any controls for any of it. I am on LW 10 when I load the scene I get an error about "No plug-in of type Nodehandler found with name input, would you like to load it from disk ?" I ignore this and scene loads, is this where I am missing something?
I can't speak to the NodeHandler issue, but the control is the right front box: all the other boxes just follow its rotation.

Generally to find controls for such things, and it can be VERY obscure, look for keyframes in the SE.

marke
06-10-2014, 02:08 PM
Generally to find controls for such things, and it can be VERY obscure, look for keyframes in the SE.

It took me some time to see that you don't need to parent or target or apply IK, why is box 3 not parented and yet copies the motion of box 1. Now I learn that in box 3 motion options you make box 1 the "rotation item" and heading controller "same as item", add a little offset and it works smoothly and perfectly ! I could never have solved that thank you.

marke
06-10-2014, 02:41 PM
Here's my 5 cents.
This setup keeps the boxes in the middle and is easy to animate with a slider. Because it's uses IK it's a bit snappy.

122236

Its totally classy Every4thpixel. Another cool solution I would take weeks to work out. I am trying not to be overwhelmed by the brains of these people. Many thanks

3DGFXStudios
06-10-2014, 02:47 PM
Cool setups! Funny how simple some things are. I like jeric_synergy's setup simple solution however the IK version feels more precise because there's no counter animation necessary.

jeric_synergy
06-10-2014, 04:42 PM
You're very welcome, but these are VERY simple rigs. If you want to see complex stuff, I suggest you look to Rebel Hill.

I think Bones have become too connected to IK: I remember someone rigging jet vanes to IK targets to get them all moving at the same. Motion is motion.

JoePoe
06-10-2014, 06:50 PM
I am all for rigs, controllers, IK and such....

.... but isn't this a case of three key frames and two clicks of mirror?

the three keys...122255 122256.

After mirror x and mirror Z..... 122257

jeric_synergy
06-10-2014, 09:42 PM
I am all for rigs, controllers, IK and such....
.... but isn't this a case of three key frames and two clicks of mirror?
the three keys...122255 122256.
After mirror x and mirror Z..... 122257
I'm embarrassed to admit that I never noticed MIRROR ITEM before (gadzooks!) :foreheads :bangwall: 8~ , but while I see a "mirrorX/Y/Z" in the MENU EDITOR, they don't appear to work in Layout. --Their lower-caseness makes me think they are from the Modeler plugins of the same caseness.

Are yours 3rd party?


(I also couldn't get the points of the cube to not cross over an axis with just 3 keyframes....)

Here's one advantage to using MOTION CONTROLLERS: you only need to change ONE set of keyframes to alter the speed of everything.

jeric_synergy
06-10-2014, 09:49 PM
I think I see the difference: MIRROR, versus MIRROR ITEM.




MIRROR is the full meal deal with all axes and a dialog.
MIRROR ITEM seems to be a quick shortcut for "MIRROR X", effectively.



JoePoe, thanks for the wakeup call!

JoePoe
06-10-2014, 10:34 PM
Well, I'm embarrassed that I'm still in 9.6 .... but, I think you're seeing the same thing.
In Layout I used Mirror: Items tab > Items > Clone > Mirror.

Also the crossover issue with just a couple keys is achieved with a tiny tweak to the tension on the H rotation on the middle key. I think it's -.5ish. (Beginning and end of motion have tension of 1.)

I will say this though.... with a good "rig" a tweak to the initial box will possibly cascade through to the others so a re-mirror won't be necessary.
edit: oops I think that's what you said. :)

marke
06-11-2014, 12:03 PM
but while I see a "mirrorX/Y/Z" in the MENU EDITOR, they don't appear to work in Layout.
JoePoe is it ...select item, select clone, then mirror that ? Can't get this working. Your setup has the cubes not returning to original positions which is a must but it is neat

JoePoe
06-11-2014, 02:04 PM
In order to get the cubes to return just copy the middle and first key frames to spots further down the timeline.... don't forget to set tension. Which for some reason isn't copied with keys??
(delete boxes 2-4 first..... make new keys, then re-mirror. This is the shortcoming I was describing, but in this case no big deal.)

Updated scene below (uses the same box object so it's just the lws.)

And, yeah.... select object and Mirror (one of the two options when clicking on Clone). That's where I found Mirror... 122274 122275

jeric_synergy
06-11-2014, 04:39 PM
If they need to continously move, use Post-Behaviour: Oscillate.

It'd be nice if we had the equivalent of AE's "loop" behaviours. (IE, "loop 5 times then stop holding last keyframe value.") Maybe RELATIVITY can do that.

MOTION MIXER would do this, but last time I looked it was both hideously awkward and heinously buggy. :P

JoePoe
06-11-2014, 05:51 PM
Yeah, not too bad with Modifier > Channel follower.
I set the main motion on a null this time and have the boxes following that.
All that's needed is to specify an end frame (well, and some of the scale values have to be negative).

Here box one goes through 1.5 cycles and stops at frame 60 (last actual real key is at frame 40 :hey:) while the others continue with oscillation.

122286

jeric_synergy
06-11-2014, 06:05 PM
Any of the constraints will allow easy keyframing, but in general it'd be nice be able to say "5 loops and quit". But even better if it were like Cyclist, and looped a SET of related keyframes, then quit.

bazsa73
06-12-2014, 03:16 AM
This is my version. I added two nulls, one is aside the other is bside.

This is my first expression. Took a few hours to find out how to set this up in LW.
So when I move the NULL "aside" on Z axis, bside's Y value is calculated in the following manner:

sqrt( (1 - ( [aside.Position.Z,Time] * [aside.Position.Z, Time] )) )

which is a derivative of this formulae: x^2 + y^2 = 1

122288

I only extend this out on one axis but it's not very complicated to add more elements.

marke
06-16-2014, 12:16 PM
Impressive bazsa73 but way beyond my understanding, thanks for your input

bazsa73
06-17-2014, 05:46 AM
Impressive bazsa73 but way beyond my understanding, thanks for your input

You are welcome, if you know the pythagorean theorem then it does make sense.
Here: http://en.wikipedia.org/wiki/Pythagorean_theorem

122417