topic Re: Autocad Drawing help in AutoCAD Forum

Autocad Drawing help

Anonymous — Wed, 21 Mar 2018 14:53:52 GMT

Kindly help me in completing this drawing?

john.vellek has embedded your image(s) for clarity

Re: Autocad Drawing help

pendean — Wed, 21 Mar 2018 14:36:47 GMT

Ask your instructor or fellow students for help and/or guidance with your assignment. There is sufficient information to complete it.

If you get stuck somewhere specific please ask.

Re: Autocad Drawing help

gotphish001 — Wed, 21 Mar 2018 14:59:01 GMT

Dean is right there is a couple things missing to draw it accurately. You can get started by drawing a small X that will be a place holder for circle center points. Then put that where a center point is and then copy it to the other center point locations using the linear dimensions. Then draw a bunch of circles using the radius that are listed using your X center point place holders as starting points. After all the circles are draw you can erase your X place holders because they were just temporary guides. Now use the trim command to trim out all the parts of the circles that you don't need. There are a few radius that you don't know were the center point is supposed to be. Maybe you could draw that circle off to the side and then use tangent snap to get it in the correct place. It's hard for me to see if it would be accurate that way without drawing the whole thing.

Re: Autocad Drawing help

TheCADnoob — Wed, 21 Mar 2018 16:18:25 GMT

Its all there. you can use geometry/trig to get the missing information. Post your progress if you need help

Re: Autocad Drawing help

gotphish001 — Wed, 21 Mar 2018 16:23:59 GMT

Did you just use tangent snaps or circle tan, tan, radius option as I mentioned for the top left R20 or was there another way to find that radius?

Re: Autocad Drawing help

TheCADnoob — Wed, 21 Mar 2018 17:46:58 GMT

I did assume that the two radiuses were tangent to the other circles so that may be incorrect.

For simplicity i used the circle tan tan radius, but there is another way if you want a brute force method.

If you assume any two circles are tangent to one another at a distance of Rt around the center circle 1.

Rt = r1 + r2

So basically around your first circle you draw an additional circle that is a radius of Rt.

so if we need to find the point at which three circles are connected only by tangents you just repeat the last step with the new circle.

Rt2 = r3 + r2 (assuming r2 is the circle common to both tangents)

If they can be tangent to each other there will be a location where Rt and Rt2 intersect. This is the location where you put the center of r2.