WM2D section....

[JohnnyD]

Could we have a WM2D section with questions, tips, scripts and all things related to it. That way it would all be in one place without searching all over the place.

JOhnnyD

[rlortie]

JohnnD,

There is a twelve page thread devoted to WM2D

http://www.besslerwheel.com/forum/viewtopic.php?t=822

Ralph

[rlortie]

There has been a lot of conversation lately regarding WM2D, so I thought I would bring this old thread out of the closet. Some may find this thread useful.

As for me, I am looking for an orthographic projection application that can simulate in 3D or animate XYZ planes. Also someone who knows how to use it and is "Patent" minded rather than free sourcing.

Ralph

[Jon J Hutton]

I'm trying to place a small circle on a large circle, the large circle spins by a motor and the small circle always stays upright by the gear icon. What am I doing wrong. I can't get it to work.???

[ME]

Your small wheel is pinned to the large wheel. Remove the gear, remove the pin, reapply the gear.
To keep it up there you could connect the small wheel with a rod to the background. It probably doesn't like that, I get an "inconsistent constraint" error.
Or use the MT13 option?

[Fletcher]

This is a question for the WM users out there.

I hate trying to build latches and catches etc. I think I've said this a number of times. They take a lot of computational effort and add layers of complexity to a design that may make it 'bomb'.

I prefer to use simple connections such as rods, rigid joints, separators, dampeners etc, and turn them on and off as needed.

But there is always the timing issue of when to 'let go' and 'reconnect', once the timed action is completed.

I sometimes use IF statements in the 'Always' field. This works but you have to adjust with Time Inputs.

Sometimes I set up Outputs of x and y position and drive the IF statements with those. But that can be cumbersome.

Sometimes I measure the wheel background rotation (in degrees) and use that in the IF statements. This is generally the best.

BUT .. sometimes I want a wheel to make more than one revolution whe I'm testing something, and that complicates things coz once past 360 degs it keeps climbing and things stuff up.

Once, a long time ago, I built an Output of Rotation that reset to 0 degs each 360 degs of rotation. Now I can't remember how I did it. Was it Radians, I don't know ?

Anyways, I need an Output that resets rotation degs to zero every full 360 cycle ?

Then I can reliably and simply use this Output to drive the If statements in the various simple latches and catches I have talked about. And so can you.

Any help much appreciated. I know someone must have come across this before and solved it.

[ME]

I simply use this (SI degrees):
Rotation

• Body[1].p.r

Range [0..360]

• mod(Body[1].p.r,360)

Range [-180..180]

• mod(Body[1].p.r+180,360)-180

By the way, it's in error on negative values... I use a (+360000) for the easiest solution.

[Silvertiger]

WM does its rotation outputs as a position in space relative to the radius of travel, a cartesian solution. For exampe, Body[#].p.r. Couldn't you use something like that? Just an idea, as I suck at these things.

Edit: Looks like ME was posting at the same time...he looks like he knows what he's doing lol.

[Silvertiger]

Here is what I would love to have in WM:

1. A water/buoyancy script.

2. A script for creating a force between two objects rather than the between an object and the background.

3. A script for creating a realistic pulley system, where you can specify the radii of the pulleys and the anchor points.

[Fletcher]

Tanks ME and ST ..

I'll try the Mod ME - mod(Body[1].p.r,360) .. may have some questions later when I get to it.

ST .. I built my own buoyancy formula many years ago when looking at pressure and depth etc (may have uploaded the sims at the time) - simply add a normal force vector and put a formula in the Fx or Fy Newtons field.

Also did the same for Lift and Drag in Flight

Just ... Lift Newtons = Cl1/2pv^2s etc for Drag

Came across a sim many years ago that had a proper pulley system. I think I asked Gregory once to upload it so have a search for it.

I'll look later but don't think I've got it.

Don't know what your number 2 is about ?

[Silvertiger]

Hey does your buoyancy formula take into account the amount of displaced liquid? Thanks.

[Fletcher]

Can't remember at the minute - that was about 10 years ago. Same with the pulley sim - had my laptop with those sims etc stolen about 2 years ago - and silly me didn't have an external backup of them.

If I built them once I could do it again, but I don't want to spend the time looking at google for the formulas (no scripts required) and then blahblahblah.

But the process of building your own is educational.

[Fletcher]

Here's a pulley sim I found.

[Gregory]

Hey Guys,

Sorry, I rarely read everything on the forum, and found this topic just now.

1. A water/buoyancy script.

2. A script for creating a force between two objects rather than the between an object and the background.

3. A script for creating a realistic pulley system, where you can specify the radii of the pulleys and the anchor points.

1. No idea... perhaps with simple force objects controlled by complicated formulas you write yourself. :)

2. There is no script needed for that, there is a nice workaround. Use the simple spring object, attach it to two bodies, and set it to constant force spring, aka the "K" type. Then set the force in newtons. This will continuously apply the force between the objects. With the active when textbox it is possible to control when to switch on/off.

3. I attach a pulley sim.


For the 360 degree reset, it is also possible to use Sin() and Cos() functions (just make sure to use radians inside), as those reset every 360 degrees, so you can know what orientation your object is at any given position/time. Sure it is complicated to work with, but I simmed "electromagnetic" motors based on this, it works perfectly. IF the sin() or cos() of some object is bettween v1 and v2 values, then, else, and all the likes...

For latches and catches I usually use force pairs (so they can cancel out without modifying wheel motion) or spring pairs, and a piston. At some point the piston slips out or slip into a region where it is catched by the forced/springed contacting objects, something like that. (I try to attach a simple example) And that can be controlled by rotational orientation for example based on sin/cos, or some object is at some distance to something, etc. Check the spring mechanism attached. Also, simplest way to latch/unlatch is with a rigid joint or rod object with active when control. Unfortunately, that can be buggy or unreliable in certain situations, sometimes without any logic.