Hey guys I am a beginner in SketchUp (Web), and I am struggling to create tangent connecting to a circle. I am basically trying to connect 2 of the circle with tangent, and advice or guide?
It would probably be easier if you leave the circles flat and work center on the origin and up the blue axis. With the free version the most straightforward option is probably to just eyeball the starting and ending points. I used 48 sides for the circles here. I started the edges from the first vertex above the horizontal on the smaller circle and ended on the first vertext above horizontal on the loarger circle.
With the desktop version you could use an extension to identify the common tangents. Here’s the result of running that extension and you can see that the true tangent points are very close to the points I used above. The guidepoint identifies the true tangent point.
The true tangent point is just slightly below the vertex on the top
And slightly below on the bottom. I had to zoom in quite a lot to be able to show it.
I think you’d be close enough using the vertices. You could do some calculating to figure out the angle of the tangent line but there might not be much value in the time spent. If you want to calculate the tangent between the two circles, look at this: Finding External Tangent Points for Two Circles – Andy G's Blog
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Here’s a workflow that makes quick work of the whole thing. I used the vertices for the tangent points from the first part of my previous post.
Since it’s symmetrical modeling half of it and flipping the half to make the other side reduces the number of steps.
- Flat profile.
- Extruded to half the web thickness.
- Draw the bottom circle and the horizontal edge.
- Extrude the faces with Push/Pull.
- Draw horizontal edge on the opposite side and push in the face above it to create half the yoke.
- Use Flip/Copy to make the other half.
- Erase the seam line edges and make it an object checking to see that it is a solid.
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Here’s a method of manually and accurately finding the tangent between two circles for something like this part. In reality you wouldn’t need to draw the circles. I just included them as a reference. Obviously if you’re using SketchUp for Desktop, TIG’s Tangent Tools would be faster but this gets you to the same point without extensions so it would work in SketchUp for Web and SketchUp for iPad.
Video straight out of SU without any edits.
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A key point in @DaveR’s method, shown in his video, is that the original circles aren’t used in the final geometry. Rather, they are deleted and he draws two new arcs between the accurately constructed tangent points and the line of centers of the two circles. This technique places vertices of the two new arcs exactly at those points, avoiding issues with SketchUp’s segmented representation of circles and arcs because vertices of SketchUp’s circles and arcs are exactly on the real radius, whereas the segments are chords that only match the radius at their end vertices..
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thank you very much, it helped me. I love the detailed response and video