Help with MS Physics modeling ball-and-socket chain (prefer dlownload).eight

advice

#1

I (volunteer intermediate beginner) am trying to model a ball-and-socket chain running through eye-hooks suspending a cardboard geodesic projection dome for the Explorers Club’s new planetarium. Have not been able to find anything in the Warehouses except hardware.


#2

I have a hunch you mean Ball Chain, akin to the pull chain on a lamp.
Like so … ?

It’s best to use a texture image for such things vs. modeling mass amounts of tiny spheres.
See this model for ideas:
Ball Chain.skp (67.7 KB)


#3

Thanks, Geo, that’s exactly what I wanted. Now I still need the end link to couple two such chains together or form a loop. Also, can you point me to an eye-hook through which such a chain can be routed to change the direction of pull (as well as how to pull it … just with the Move tool?)

Thanks, jenterli


#4

How about I teach you how to fish instead of pointing out where to find a fish dinner?

Model performance issues often stem from modeling overly complex tiny geometry.
It’s best to model small curvy things with as few polygons as possible.

Watch this Circle tool video and you’ll learn how to dial down the number of segments in a circle.


Then learn how to extrude the low poly circle along a path with the Follow Me tool.

Here’s a screenshot of how to set things up.


#5

Thanks, Geo, for your excellent tutelage. Next time you’re in NYC, look me up and I’ll take you to a nice fish restaurant.

I’m still a little mystified how to thread the chain through the eyes. Could I just place it over the eyes and let it cut through them to the interior, then solidify the arrangement somehow?

jenterli


#6

There is no collision detection in SketchUp.
That is, things don’t go bump and stop like in the real world.

You can place things on, in or through others any way you please.
Objects you’ve modeled in SketchUp pass right through one another as if they were made of smoke.

It’s all good, at least until two edges touch. That’s when things get sticky. (literally)
Whenever and wherever edges touch, they break at the junction and inexorably stick together.
Imagine trying to build a real world model with strips of flypaper and you’ll understand SU’s sticky edges.

The way to keep things from sticking together and organize your model into manageable objects is to build the first object and then immediately isolate what you’ve just modeled before modeling the next object.

In SketchUp…
Making a selected set of geometry into a Group or Component, aka grouping, is how we isolate geometry.

Think of Groups and Components as invisible containers.
Geometry inside the container is isolated and protected from sticking to everything outside the container.
And if you decide to move the container, everything inside moves as one.


#7

Yes, Geo, I believe I understand all that. But I think it does not address my question about
threading the chain through the eyes. I assume the chain you sent me arrived as a group or component. (If not, it could easily be made one.) Then couldn’t I just (deftly) place it over a newly created eye bolt and let it cut through to the interior hole of the eye, being careful not to let it stick to the walls? (This would take zooming in to work carefully.) Then one would solidify the arrangement by immediately selecting the eye and making it its own group. They would subsequently be kept from sticking together, no?

If the answer is no, then is there some kind of joint that could guide the chain in a similar way to what I want to do?
jenterli


#8

Keep the Entity Info dialog open while you’re modeling so you can identify what you’re working with.

Once a set of geometry is made a Group or Component, it won’t stick to anything…
Be it another Group, Component or raw geometry.

It’s best to never leave raw geometry in the model.
And making Components is a far better choice than making Groups.
Especially so when you’ll be making copies of an object.

Simply model the first object and make it a Component.
Then model your next object and make that a Component
…and so on until you have all the objects you need to assemble whatever larger structure you’re building.


#9

Geo, it’s beginning to sink into me that in SketchUp, even with MS :Physics, there is NO way to simulate the actual pulling of the pull-chain around a corner or guide without the chain just cutting into the corner when pulled.

However, I recently came across a new release about MS Physics Curvy Joints, which looked promising. However, I was unable to get the audio portion working in my system (true of all the MS Physics Tutorial videos). Any info on how to approach that? Is there a new model?

jenterli