Sketchy physics - rotating a crank


#1

I’m having problems with rotating a crank in sketchy physics. Any help?

  1. I draw a 3D Circle, a crank and create a group
  2. Adding the “motor” on the axe
  3. play = Ok
  4. Add to columns to support the crank (with a hole where the crank pass through)
  5. play (a small movement and nothing)
  6. I Add a “Hinge” to the columns (join between Column1 + Hinge1 and Column2 + Hinge2)
  7. not working :frowning:
    It could be nice also to have a good tutorial.

here after the picture of the SU project

and a example of a classical whirligig whale

Thank you
Phil


#2

Hi there,

From your illustration, it seems like the hinge is off center. (to the rotating axis).
-Which will hinder the rotation.
The hinge is added to the columns, but they are apparently not lined up to fit the line/center of rotation. (sorry for my English…)

But it would be much better for the problem solving if you could upload your model. Thanks


#3

As for tutorials here is one:


(I have some more somewhere… see where this gets you first :slight_smile: )


#4

Hi Piiil60,

thanks for your help, I found also a very interesting tutorial here:
https://www.google.be/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.niutec.nl%2FTekenen%2FSketchUp%2FPlugins%2FSketchyPhysicsTutorial.pdf&ei=OUWVVbuZBMPpUqLWgbAB&usg=AFQjCNGPQF-T8uVnhZeNY68zxnCaTnkpzg&sig2=NAZuJiUDWtyvwYMPrOV_nA&bvm=bv.96952980,d.bGg

I found two things to help me in the resolution of my issues:

  1. “drill” a hole in a 3D object is not “understood” as an empty space by SP.
    To create a hole, we must group objects in order to design the hole.

  2. by using the “Debug” option, I realized that the crank is not viewed by SP as a wire but as a cube (an envelope all around the crank). So I resolved my problem by setting the state of the columns to “ignore”.
    Now the crank and the circle move freely.

I will continue with the rest of the project and of course, I will keep you inform!

Best rgds,
Phil


#5

Thanks Phil.
Looking forward to see your project.

There are models with SP at the 3D Warehouse too.
https://3dwarehouse.sketchup.com/index.html
Lots to study there.
Good hunt to you!
Cheers


#6

Hi,

I designed a quick rough version (just to be sure that the model works fine)

Now, I’m ready to work on a whirligig model

Phil


#7

Hi,
Thanks for sharing :slight_smile:

Been kind of busy here in this heatwave, but/and would like to try your model.
Maybe you could upload the file here for everybody?Thanks.
(instead of signing up for Dropbox…)
Wish I had more time for all this fun stuff!
Cheers


#8

Hi,

I worked all the day on the project and no way to design a real case!

what I learned today:

  • if the model is too small, there is no physical interaction (may be due to tiny numbers in the formulas); so I multiply the size of the whirligig by 100
  • if you want to attach 2 joints to the same 3D object,
    • joint 1 + Group 3D Object
    • joint 1 + Define parent
    • Explore the new 3D object group, clik on the 3D object to isolate it
    • joint 2 + Group 3D Object inside the first group
    • joint 2 + Define parent

Sorry but I don’t know how to attach a file directly in the forum, so I used Drop Box again


#9

That is a charming whirligig!
Well you can upload here:


-or drag and drop.

Several years since I tried SP so I don’t remember much…
It was lots of work to learn. That I remember :slight_smile:
Maybe this model to study is close to your project?


#10

Hi,

I finally solved my problems with the whirligig.
What I learned today (stay positive :slight_smile: )

  • It’s very important to set the joint very precisely (an offset can have a huge impact)
  • when nothing works, set a name to the joints, you can play manually the animation … and keep calm :slight_smile:
  • Check examples on the warehouse … if you don’t find exaclty your solution, at least you will see people doing things really more complex that what you are trying to achieve

It could be nice to have a dedicated forum for SP; there are so many things that we can do (… and so little documentation :()
I hope that a new 64 bits will come soon (now I have to work with SU 8 with SP and SU 2015 for my other projects) - No way to install on the same computer SU 2015 32 and 64 bits

Rgds,
Philippe

Here after the whale in SU
Whale-animated-V2.1.zip (748.8 KB)

Preview of my new projects in progress …


Modeling a Ring (Circle with a Hole in it's Center.)
#11

Hi!
Thanks for model.
-I did find out how to download from Dropbox though ( Dooh, didn’t have to sign up)

So I ended up spending time on SP in my weekend too… :wink:
-and learned something too, I think…

Your solution to transferring the red/blue plane rotation to the green/blue plane is quite interesting and innovative.
Well, I wish I had more time right now, but must go to work today.

Your new projects, do the wheels spin too? :wink:

About other forums:
maybe you have been here: http://sketchucation.com/forums/viewforum.php?f=61
or here: http://sketchyphysics.wikia.com/wiki/SketchyPhysicsWiki

Regards

Edit:

I agree