Copy Function

Is there a way to consistently make a copy of something (in this case a line and sphere, with the line coming out of the surface of the sphere) directly on top of the reference and then rotate the

I think you didn’t finish asking your question so a WAG.

Are you still working on the bead chain sprocket? Are you trying to draw the chain with the beads and links? Something like this?

I made the link a separate component from the bead. Use Move/Copy to copy the link between the beads and Rotate/Copy like I did for the beads around the sprocket.

Oops, I didn’t think I had posted that message!
Yep, still at it. I really don’t need to model the chain, just its associated sockets on the sprocket. I was trying to figure out how to place 11 spheres equally spaced around a circle, but I think I have that now. I am figuring out the Array copy with the rotate tool. That seems to be a quick way of getting equally spaced spheres arranged in a circle. I have also tried your subtract tool as you showed me earlier. That is actually quite straight forward, so am good there. I am still struggling with the basics, for instance, trying to find the center of a sphere or its center as a result of a projection on a flat square face, so that I can quickly position the sphere where I want it to be in space. I have to get better at inferencing - that may solve some of my issues. I never realized I could copy with the rotate tool, so that will make it easier, but I need to nail down array copying with the rotate tool as well. Copying 11 spheres is no big deal, but when I get 50 -60 spheres, it will become an issue as my sprocket sizes get larger.
I have also come up against some limitations completely out of sketchup’s hands. Ball chain sprockets, for a given ball size, have diminishing pitch as the number of sockets decrease, which I just discovered. So although I want an 11 socket sprocket, the chain pitch circle is getting so small, it may be encroaching on the diameter of the center through hole in the sprocket.
Again, thanks for your help. Am much further ahead than I was a week ago!

Copying with the rotate tool is as easy as copying with the move tool. If you know the degrees you can select the object you want to rotate, choose the rotate tool, click once to place the center of rotation and press option (CTRL on windows) to start rotating a copy. Then let go of the mouse and type in the desired degrees of rotation. Then you can type x and a number of iterations to repeat that copy around the circle.

However, another method, which took me years to catch on to, can be used if you know the number of objects you want to array and don’t want to calculate the degrees between objects, or if you want to experiment with different arrays. Start the same way by rotating a copy, then enter 360 and enter to move that copy completely around the circle and place it on top of the original. Then enter / and the number of instances you want to exist.

Thanks for that, Riley. I have tried both methods your described with success. One area I still struggle with is getting the sphere and line (either imaginary or actual line from the sphere to the rotation point) to meet at the center of the sphere. I don’t seem to see any inference points when I select the sphere (which is a component). I see little red marks on the component face that seem to work with the compass icon, but I cannot accurately find the the point of the sphere that touches the component outline. In your example above, the red axis has to meet the center of the square projected by the sphere. How was that done?
Thanks for your help.

When I made the sprocket I drew the profile of it to include the groove for the links as part of the profile for Follow Me. This was based on the information provided by the manufacturer whose dimensions I worked from.

I have done the same thing in the profile I have made up for the sprocket. In my first attempt I was trying to make the groove without using the FM tool which turned out to be impossible to do with my current skill set. Your idea using FM along with the profile was very simple and elegant. I thank you for that.
I tried to speak with the manufacturer of those sprocket wheels you identified. He, unfortunately is no longer in the sprocket business and couldn’t provide any additional info on ball chain pitch. I did find a 1958 patent on sprocket wheel design with some info though, which has proven useful.

Would still like to find an easy way to join a line to a sphere such that the line is perpendicular to the face of the sphere. This, combined with Riley’s array copying with the rotate tool would be a very quick way to produce the chain pattern that I can use with the sprocket profile.

Thanks for the help.

This tells me you don’t quite understand the geometry of sketchup. It would either need to be perpendicular to a specific facet of the Sphere or a Vertex or an Axis. All are possible but you need to understand the difference.

1 Like

If you closely examine a piece of the beaded chain, you’ll see that the wire link between the balls is loose in both of them. I think it would be more appropriate to model a cylinder and make it a component separate from the ball as I did. It also make it easier to get those wire links positioned correctly between the beads as you copy them around.

Maybe my terminology is wrong. The sphere I have modelled is a component. Triple clicking it produces a mesh of the sphere. Where the meshes meet around the poles of the sphere produces a single dot at each of the mesh poles (I seem to get a figure of 8, not sure why). One of those single dots has to be joined to the end point of my line, which is a specific length. That will produce a sphere perpendicular to the line. It is trying to find an easier and repeatable way to get to that dot that is causing me problems. I thought by simply clicking the component and finding the center of any of facets of the blue cube around the sphere would produce the same result (then I don’t I have worry about the orientation of the sphere itself inside its component cube). However I can’t find a way identify the center point of any one of the facets (which are squares) of the cube and join that point to the end of the line.

The length of the line, combined with the radius of the sphere produces the radius of my chain pitch circle for a given number of spheres i need to produce the sprocket…

On my phone about to sleep so can’t produce a gif.
When you make a sphere you can decide how to position the circles.
If done deliberately you will have a face set perfectly on each axis.
No doubt someone will show you while I sleep.

Graphics card limitations most likely. It is a single point.

You should be able to use inferencing when you draw the circle for the diameter of the wire. Center it on the pole of the sphere and locked in the correct direction. Here I’m drawing the wire on top of the sphere and pulling it up in the blue direction so up arrow key to lock the direction.

1 Like

Dragged myself out of bed to do an axis face. You need to position the circles to get the faces of the sphere how you want them.
Sphere geometry

Could it be that some of your issue stem from not knowing about the underlying hidden geometry.

Thanks! Will give this a shot.


Ok! First sprocket model done! Thanks for all your help!