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3ds max constraints

Hi all,

I'm working on a rig for a 1066C Koehring excavator and have run into a problem with the bucket linkage rigging. Everything is linked to each other except one linkage bar. In the below photo, I want to link number "2" to "1". Any idea's? excavator-link.jpg?t=1263968026

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  • Neil87
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    Koehring 1066C excavator.

    koehring-1066C-resize.jpg
  • Mark Dygert
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    Arrg precise mechanical real world machines...

    How about using an IK chain? The base of the chain starts at #2, and the tip follows the tip of the piston. It would probably be pretty easy to push that past its limits and break the effect, but its probably a good place to start. You can probably experiment with a limit controller to get the pieces to stop when they should.

    Something tells me if you want a robust rig thats hard to break you're in for a long night of wire parameters and script controllers.

    Here's a good set of video tutorials that cover all of the constraints, including limit controllers.
    http://area.autodesk.com/louis_tutorials/animation_and_rigging_techniques_for_architecture_visualization

    Wire parameters and script controllers well... those are not so easy to pick up or teach.
  • apocalypse
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    apocalypse polycounter lvl 18
    Vig is right, you're in for some tough times. I'm just starting to learn rigging myself. I came across this tutorial which may work for you. It's a maya tutorial, but same shit different name (imo).

    http://www.wonderhowto.com/how-to/video/how-to-create-a-working-piston-using-maya-970/view/
  • Neil87
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    Hi guys, Thanks for the tips and links. I still have yet to get that one linkage point to follow the rest of the main stick. Everything else works (cylinders with look at constraints, hoses that flex). The main boom uses a IK spline which runs from the boom mount pin to the boom-stick pin and finally arrives at the bucket pin.

    If I were to use an IK chain, how would I go about linking that to the main spline but at the same time, allowing it to rotate? (Working with 3ds max 7)

    Also, I used a path deform modifier to make the tracks however the individual track shoes are bending to fit the spline when they should should remain rigid. Any ideas?

    render36.jpg?t=1264181490
  • Mark Dygert
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    You can try rigging tank tracks with bones which will give you rigid tracks. Quite a bit of work but he covers some wire parameters to help automate the animation, pretty cool stuff. http://www.3dluvr.com/content/article/136/1

    You might want to switch the spline IK on the main arm to a IK limb solver and use bones, it will probably handle the rigid motion a little better and allow you to attach other bones to specific areas. Spline IK might be a little soft and spongy for something this mechanical?

    As for the complex bucket joint I don't see any way to do that other than with expressions and a scripted controller. The idea I previously had about using an IK chain would only attach to the main arm and follow the tip of the piston and works if the tip of the piston only slides forward and back and never rotates up or down, which it does... breaking the idea I had.

    You need it to work with the other arm to adjust the rotation of the bucket which effects the tip of the piston. There's only only one real way I can think of to get that done and that's with wire parameters and scripted controllers.

    You're starting to venture out of standard basic rigging and into advanced mechanical rigging and most of the answers you need are tucked away in a small handful of dvd's, and in teachers who generally get paid obscene amounts of money to share what they know...

    In other words I think you're past what any free forum can provide, especially one that focuses mostly on modeling and materials =P

    http://www.3d-palace.com/cgshop/product_info.php?cPath=14&products_id=55
    The Crux, covers some pretty complex rigging but, I don't remember if it covers anything like that joint, mostly just what you've already been able to do on your own.

    If you're serious about learning scripted controllers and are pretty competent at teh maths you might want to ambush Paul Neale with a suprise email and see if he can point you in the right direction. He's a great guy and likes to help but he's not the type to do it for you.
  • Piflik
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    Piflik polycounter lvl 12
    It is a quite simple setup, once you get your head around it ;). Just some Bones with an HI IK and some Linking...

    I did a little sample scene. It is horribly out of scale and uses just simple geometry, but I named everything, so you should be able to recreate it.

    Click! (Max2008 )

    If you have any questions, shoot ;)

    And before you ask...you'll animate the Object called Control ;)

    Edit: Vig, I first also thought about Expressions and/or Wiring and wanted to dig deep into my brain for the appropriate Math, but once I stopped thinking of that Bar as Slave and made it the Master instead it was quite fast a fix ;)

    Although...now that I think about it, it should work the other way around, too...wait...no...it doesn't...ohh...drat...it does...I am stupid...and confused...:poly142:

    Here's the same Scene, just with the Bucket as Master...take the one you like best...they both work...

    Click!
  • Mark Dygert
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    Facepalm... Yea that just needs to solve in reverse of what I was thinking, HI Solver... duh didn't even think of it... double facepalm.

    Nice fix!
  • Neil87
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    Wow guys, great responses and fast! Piflik, could you please post a screen shot of that file. I only have 3ds max 7 and I could not open it. Also, thanks for that track tutorial link Vig.

    This is machine is for my own self satisfaction and I wanted to expand my knowledge of just modeling in 3ds max.
  • Piflik
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    Piflik polycounter lvl 12
    Sure...here you go...I hope you can decipher my scribblez...

    ExcavatorScreen.jpg

    Bucket is linked to the Control Object (a simple renderable Spline), The Control Object is linked to the Arm. Then I created a 3-Bone Chain (2+End) from the Joint you called '2' in your screen across the Piston Joint to the Second Joint at the Bucket (the Bucket's Pivot is at the other Joint!) and applied a HI Solver to it. The IK's Target is linked to the Bucket, the two Bars are linked to the corresponding Bone. I linked a Point Helper to the one Bar, to control the Pistons (via Position and LookAt-Constraints). Now if you rotate the Control Object, the whole assemby will move accordingly (You can skip the Control Object and animate the Bucket, but I like Controls ;)).
  • Neil87
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    Thanks again Piflik

    I created another temp boom rig for the purpose of simplicity. I used your method and it worked! The only problem, when I move the boom, Joint "2"(as in the above screencap) it comes apart. I have tried to link it but can't seem to get it. Also, how would I add this method to the rest of the boom assembly?rig-help2.jpg?t=1264280875rig-help2-1.jpg?t=1264281266
  • Piflik
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    Piflik polycounter lvl 12
    Oh...right...forgot to mention...the first one of the Bone Chain is linked to the Arm...

    It should be no problem to integrate that into your Rig. You just have to create the Bones (if you activate the Bone Tolls, you can edit the Bones after creation and align them perfectly to the Joints), IK them and link the Bars to them (in fact you could also build the setup without Bones, if you link the Bars and IK them...you'll need some additional Dummy Object to simulate the End Bone).
  • Neil87
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    Success! Thanks again Piflik and others. I will post a rendering here later on! The last step would be the addition of limits for the cylinders. Max 8 seems to have a much easier approach.
  • Neil87
  • Neil1987
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    It's been awhile but I've dug this out to finish. More details and textures added.

    8xbs.jpg
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