How do i find the center of this tube?

Tekkybot · 14 Sept 2008, 18:25

hi guys. i absolutely can not figure out a way to find the center of this tube. what i want to do is create another thinner tube inside it. and to do that, i need to first find the center of the tube, so i can create a circle the size of the inner tube and then use the follow me tool to make it a tube.

the problem im having is i cant find a way to find the center of the tube with out a flat backing circle face.
and with out a center, i cant make a circle backing face. another thing, i was able to a few times find a way to just click on the tube, and use the green inference like to find the center point, but i have no idea how i did that and i cant do it any more.

when i click on the move tool, the following 'red' whole protractor appears and does exactly what i want, but i can't make it draw any lines. only the half protractor draws lines and it doesn't designate a middle and center like the 'red' whole protractor does. i did get the half protractor to designate a center a couple times but i have no idea how i did it. please help

EarthMover · 14 Sept 2008, 19:48

I would just draw a square that touches the circle on all four sides using the line tool and inference. Then use the tape measure tool and pull reference lines to the center of the opposing lines. Do this on two sides and where they meet is the center of your circle. Make sure to group the original circle so that the center points on the sides of the square are retained.

I generally use the "point at center" ruby as the easy way to find the radius point of any circle or arc.

Bep · 14 Sept 2008, 19:56

You have probebly exploded one of both circels into line segments.
Check with "entity info" with wat kind of entity's your dealing.

Kind regards.

Bep van Malde

Chris Fullmer · 14 Sept 2008, 19:59

Good technique. I found it by drawing an arc over a few segments, and then matched the arc to the amount of segments i drew over. So for example, I marked off 9 line segments. Then I drew an arc from the beginning to the end of those 9 segments. Then I typed in "9s" to get 9 segments in my arc. So now my arc is drawn perfectly over the top of the existing portion of the circle. Now that there is an arc there, right click on it and choose "Point at Center". That will place a construction point at the center of the arc, which is also the center of the existing circle, since my arc is perfectly aligned to the circle.

So thats another way,

Chris

Alan Fraser · 14 Sept 2008, 20:00

If that thing is grouped, just go inside the group and select the inner circle, then copy it. When you've done that, close the group then go to Edit > Paste in Place. This will copy the circle on top of itself...but the two versions won't merge because one is inside the group and the other is outside. Just select the new copy that's outside and scale it smaller.

Hazza · 15 Sept 2008, 00:56

Download the Set centre point plugin.
Select the Circle.
Plugins -> Set centre point
Select the circle drawing tool.
Put the tool on the current face.
Hold the "Shift" key so that the tool keeps the orintation of the current face.
Move the tool to the guide point.
Draw your inner circle.
(Optional) Delete the guide point.

Gaieus · 15 Sept 2008, 07:04

You got a couple of advices so I just refer to the "two kinds of procractors" you mentioned:

One (the "red one") is the Rotate tool and is within the Modification tools; you rotate selected geometry with it.
The other (the "half") one is "really" called Procractor (it's in the construction toolset) and is only used to measure angles and create guide lines.

Anssi · 15 Sept 2008, 17:07

I am a lazy person. I would just use the Offset tool

Anssi

Tekkybot · 16 Sept 2008, 00:43

thanx guys. thanx hazza