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View Full Version : How to rig valve to camshaft ?



kolby
02-07-2009, 07:07 AM
Hi,
Is there any way how to rig valve to camshaft automatically without keys ?
I need it automate because of changing speed of camshaft rotation during animation.

richdj
02-07-2009, 07:44 AM
Not looked at the file, but check out William's 24 hours of training. He rigs a piston, which should help.

Rich

kolby
02-07-2009, 07:57 AM
Not looked at the file, but check out William's 24 hours of training. He rigs a piston, which should help.

Rich

I saw it, but this is little different situation, I think.

Otterman
02-07-2009, 08:23 AM
I can't look at ur files as I'm on my shiney new iPhone. Sorry had 2 get that in hehe. Anyways I would recommend the use of a channel modifier such as cyclist in the graph editor of each moving part and control the speed usind a master null. Again there are several vids from our man Vaughan on how this. Once uv nailed it ul b suprised how useful it will b for future projects. Keep us posted on your results n if you need any help just ask.

Cageman
02-07-2009, 09:05 AM
Hi,
Is there any way how to rig valve to camshaft automatically without keys ?
I need it automate because of changing speed of camshaft rotation during animation.

I looked at your files, but I'm honestly lost on what you actually want to achive... If you could describe in more detail exactly what it is you are after I can probably help....

:)

kolby
02-07-2009, 09:47 AM
It can be due to my bad english :)
But my problem is already solved. Look at my new scene. All is controlled by speed of Crank rotation, like in real engine. Maybe you can solve this by more elegant way.
Now my problem is, how to link morf of the Spring to this rig. (The morf is included in valve object)

evenflcw
02-07-2009, 11:58 AM
Why not just use all the different distances to move the valve and stretch the spring? No complex math or expression needed.

First, I set up two nulls on the cam. These define all the extreme points on the cam. Then I simply have to compare the two (+radius) to see which is the most extreme point at any given time. See expression motion modifier on the valve.

Second, place a null to define where the base of the spring and another fot the tip. Then just twiddle with the stretch amount and the offset to get an output that works. See expression tab in Graph Editor for the morph. First part of the expression is stretch, second part is offset.

EDIT: Updated the attachment. Just moved the valve back into place and parented everything to the master.

Cageman
02-07-2009, 12:50 PM
EDIT: Updated the attachment. Just moved the valve back into place and parented everything to the master.

Neat setup!

I finaly understand what this was about. :)

I would probably have used Cyclist for the main parts and a bone+cyclist to control the spring (scale.y).

:)

kolby
02-07-2009, 12:55 PM
Why not just use all the different distances to move the valve and stretch the spring? No complex math or expression needed.

First, I set up two nulls on the cam. These define all the extreme points on the cam. Then I simply have to compare the two (+radius) to see which is the most extreme point at any given time. See expression motion modifier on the valve.

Second, place a null to define where the base of the spring and another fot the tip. Then just twiddle with the stretch amount and the offset to get an output that works. See expression tab in Graph Editor for the morph. First part of the expression is stretch, second part is offset.

EDIT: Updated the attachment. Just moved the valve back into place and parented everything to the master.

Whaw ! Absolutly perfect. But I don`t know if I will be able to recreate this for all 24 valves (12 pairs with different angle and timing).
I`m not too much familiar with expressions.
But I`m going to explore your solution.
Thank you very much :thumbsup:

lwanmtr
02-09-2009, 03:59 PM
Havent looked at the setup yet, but if you need more of the valves, just parent the entire setup to a null, save the scene, then use load from scene and just place/rotate the nulls where you need them.