Contraint Issues

[Anonymous]

Currently using a position constraint on the bar to the rotator, have a question on constraining. Is there a way to do a double constrain? Meaning the top of the bar is constrained to the rotator while the bottom of the bar is constrained to the lower pin?

a video to show whats going on

http://www.youtube.com/watch?v=NH6JTRDN6jE&feature=youtu.be

[Swordslayer]

You need something to keep track of the horizontal positon to link the arm to and a point to look at. And of course a precise model in the first place, if you just try to guess it (as I did) you will end up with imprecise result, too. Have a look at the attached file for example of such approach - just barebones, no models, only two splines and a few helpers and two keyframes.

[Anonymous]

Thanks a ton buddy, I'm going to take a look at all the files when I get home tonight. I'll let u know how it goes. I really appreciate the help.

[Anonymous]

Hey I just viewed the files, this is exactly what I wanted to do but I'm confused on how you did it. I see that you have only 2 key frames 0-5 how were you able to make it do a complete 360 rotation? Also I'm lcompletely ost on what piece was constrained to what. 

[Swordslayer]

Hi, I've set the out-of-range type to relative repeat. As for the setup... hmmm, let's say that I'm too lazy to explain things thouroughly so I chose an easier route - I present to you an automated way of crank-piston setup:

First, setup your scene just like in the image below, front or top view, X axis pointing to the right, place the helpers in all the joints, plus one master helper (when finished, you may rotate the master helper any way you want, everything works in its parent space). Names of the objects are irrelevant, they are there to show which object to pick after running the script.

Next, run the attached script, pick all the objects and click setup. It's not completely foolproof but if you stick to these instructions you should end up with a working helper hierarchy. Now you can link the rod model to the Piston Pin helper and the crank model to the Crank helper and you should be set.

I've also attached sample file with three such hierarchies already set up.

[Anonymous]

Thnx a ton buddy, greatly appreciated!  Gonna give it a try, i'll let u know how it works out. 

[Anonymous]

Worked like a charm, that script is amazing! Did you create that yourself? last question for ya, whenever i select my point helper and go into the curve editor, it wont let me change the curves into ease curve out-of-range. I have the curve completely selected, not sure what im doing wrong. I animated frames 0-5 with a 90 degree rotation, i'm assuming the out-of-range will fill in the rest right?

[Swordslayer]

Yes, glad that it worked for you How are you changing the out-of-range types? It won't work if you pick the whole rotation controller, you have to do it in the particular subcontroller, for example X Rotation. Other than that you don't have to select the curve nor the keys. If there's still some confusion, the Out-of-Range Types topic of the online reference should give you all the answers.

[Anonymous]

Awesome, I seriously can't thank you enough! I was able to find it, I was going in the wrong menu lol. Its under edit>controller>out-of-range types, i was going under the curves menu. Everything works like a charm, great job on breaking it down. thanks again buddy