WM2D

[Gregory]

Graham,

Maybe this is the simplest CF demonstrating gadget. Can be made in 5 minutes. Gravity set off... CF acts against the springs & extends them out.

[graham]

Nice job Gregory. It shows a correct response to CF, thanks.

Take a look at this one. No gravity, an initial push to the weights , blue bar locked for the initial one second of time to make sure all is settled down before release of the bar.

This also shows a correct response and I take back my comment about not trusting WM2D.

Graham

[Gregory]

Looks good! A healthy model.

So, Wm2d offers its capabilities, we only have to use it properly to get the results we are looking for.

Wish you good experiments & testings.

[Deven]

Any ideas how to stop weights from flying through other solid objects?

[jim_mich]

Decrease the time step value. The weight is on one side of the object then in the next step it is on the other side. Making the steps smaller forces it to collide with the object. Of course I assume you have the object set to collide with each other!

[Deven]

Thanks Jim. That helps alot, along with changing the accuracy settings.

One more question. With the gears in WM2D, is it possible to only make rotating gears with circles or other polygons, or could you make a set of gears more like the chains on a bicycle?

[jim_mich]

Sure! Just put an idler gear in between so that the two outer gears will turn tha same way. None of the gears need to actually touch each other. You can even hide the idler gear.

One thing that WM2D cannot do is have a number of pulley circles with a belt wrapped around driving them, like on a riding lawnmower where the belt drives two or three blades at a time. Instead you need use gears.

[Deven]

Hmm... Yeah I noticed that you couldn't close a pulley system. But that wasn't really my question and its my fault for not putting it right haha. What would be extremely useful to me is a pulley system with gears.

For example, say you wanted to pull a three pound weight one foot distance with a one pound weight(or one pound of force). The one pound weight would have to move three feet. Does WM2D have this capability?

[Gregory]

Yes, both can be done with the gear tool (1:3) or by using different diameter (1:3) for the pulley wheels.

[Gregory]

Hey Rainer!

I would need your help again!

I have a circle attached to the background. I make a piston by connecting a rod from the radius to a cylinder sliding in a slot.

Now, I want something very special, and I can't find a way to do it...

Let assume the cylinder with the slot is placed on a wheel in another plane parallel with the crank-wheel.

I rotate the big wheel with the piston cylinder on it, but I want the crank-shaft of the piston to stay motionless. Instead of the movement of the piston, I want the attachment point of the piston-rod on the small circle to rotate around...

So, the piston-rod has a constant length and the attachment point rotating around on the small circle.

We do this in the case of pulleys, works smoothly & fine,
but I can't seem to do it with a piston... Looks like wm2d need the length of the rope/rod to be variable & not constant. However in the case of a piston, it must be constant.

So, is there any way to do that? If yes what's the formula which can do that?

I would need it for a very special simulation...

Thanks in advance,
Gregory

[rlortie]

Gregory,

Do you mean something like a radial engine?

[Gregory]

Hi Ralph,

Thanks for your help.

I like radial engines much, but my problem here is rather in the virtual world of Wm2d. My idea needs 3d to simulate, however I figured out I can do it and see an approximate result, if I can achieve some tricks inside the simulation...

[cyberdust]

I'm trying to learn wm2d and have some problems. How do you put friction in a joint and make a pendulous wheel come soon to a stop? I use air resistance as high as 60 kg/ms and "pin friction" but it does not help very much. I made a simple pendulous wheel and it started to spin so fast that it "exploded". What are the normal values for air resistance and pin friction?

[Tinhead]

Hi Cyberdust,

use the "rotational Damper' instead of the normal joint. Forget about the air resistance, the way it is calculated it doesn't help a lot.

Cheers,
Rainer

[Tinhead]

Uhmm, Gregory ....

I'd love to help, but I have to admit .. I don't get it :)

What is moving, what is fixed ????

Cheers,
Rainer