Dimension 2 points on a circle around one big circle

[aaliankhan5]

Hello, I am having trouble sketching a design I want to do and can't figure out how to do it. Its easier to show what I am trying to accomplish:

There are two small circles which are constrained to move along the big circle and I want to set a distance between those to circles to 20mm but when I try to do that it only lets me do it vertically or horizontally and I want to do on the perimeter of the big circle. This will later become a circular pattern around the big circle but I can't see an option where you can set the distance between the geometries(small circles in this case)

[laughingcreek]

is this what you mean?

https://knowledge.autodesk.com/community/screencast/d8fd0784-b200-44e6-998b-4a7ceaad83cb

[g-andresen]

Hi,

if the circles are to be arranged at a defined distance together I would do it, as shown in the screencast. The definition of a position (12) is only necessary if needed.

günther

[davebYYPCU]

@laughingcreek  has measured point to point, 

@g-andresen  video is  was unavailable, 

If you are using circular pattern, then pattern it, with number of circles on the circumference.

A little more work 

circumference is 200 and 36 degrees will make this arc 20 mm long.

might help.....

[aaliankhan5]

Hey, I like how you did it . can you explain more about the equation. sorry I'm in Grade 9

Edit: I got the solution. This is how I did it:

I have a circle that has a diameter of 100 and a circumference of around 304.143 mm

The equation is: 360 degrees = 304.143 mm

I want to know how many degrees are there when the circumference (304.143 mm) is equal to 1. So to make the circumference to 1  I divided it by 304.143 mm and I did the same to the other side to make the equation balanced, so

360 degrees/304.143 mm = 304.143 mm/304.143 mm

Which is equal to

 1.183653741825391 degrees = 1mm

So I just time the degree by how much length I want so

23.67307483650783 degrees = 20mm

[aaliankhan5]

sorry, but no that is not what I mean. The dimension is not following the curvature of the big circle instead it is making a 45 straight line and using that the dimension. thanks for replying I appreciate it. 👍

[aaliankhan5]

Thanks for replying. Can you explain where you got that 30.6 degrees from?

[davebYYPCU · Accepted solution]

Ok, to make it simple, 

you want the spacing distance around the circle edge 20mm.

I made a circle with 200 mm for the whole circle circumference. 10 times longer. 200 / pi = diameter

360  / 10 equals 36 degrees.

In your example we don't know how big the big circle is (50 something diameter) , so you will need to calculate the angle that will give the circumference arc length of 20mm, so that the pattern will be correct.

All the Fusion tools for this work is done with the angle.

So for any size circle it is circumference / 20mm. (x)

360 divided by that answer (x) is the degrees of angle you need.

Might help....

[aaliankhan5 · Accepted solution]

Thanks, I get it now

This is how I did it

I have a circle that has a diameter of 100. I used the inspect tool to find the length/circumference of the circle which is 304.143 mm

Now I know a circle is a full 360 degrees so the equation must be

360 degrees = 304.143 mm

Now I will find out how many degrees is 1mm by making the circumference equal to 1. I will do that by dividing it by 304.143 mm so it equals to 1 and I will do the same to the other side so it will be

360/304.143 mm = 304.143 mm/304.143 mm

1.183653741825391 = 1

and then I multiplied both sides by how long of a distance I want 

1.183653741825391 * 20 = 1 *20

23.67307483650783 = 20

[etfrench · Accepted solution]

I think you'll find your calculations are a wee bit off 😀  You can simplify the calculation like this: Desired arc length /circumference * 360.  This will give you the central angle of the arc which can then be dimensioned.

p.s. Pi is 3.14 not 3.04

[davebYYPCU]

You are correct, 23.673.... is what I got.

@etfrench he didn't use pi.

[aaliankhan5]

Great formula. 304 was the circumference of the 100 mm circle

[etfrench]

You may want to check your dimensions:

@davebYYPCU  Pi * 100 should equal the length show in Fusion 360 😀

[davebYYPCU]

Yeah and I should have checked that for myself.