Isometric with two fillet intersecting

I am trying to draw the line where two intesecting fillets meet, any help much appreciated.

isometric fillet.dwg

Is this a drawing exercise, or is there any other reason you could not do this with solids?

Yeah, a drawing exercise, and 2d only.

I can imagine it would be easier in 3d all right.

Take a look at the revised file. I've color coded the lines to help illustrate my point. First a disclaimer, your "sphere" was not properly configured to start with as all of the centers of the elipses did not match up. I tried to patch it up quick but it still may not be exact.

The first thing I did was create an isocurve (green ellipse) to match the 45* angle needed. I did this by starting the ellipse at the center of the bounding circle (magenta), set the major axis to the quadrant, and the minor axis to the "pole" (intersection of red and blue isocurves). Then I basically just copied the sphere into the fillet position and trimmed away what wasn't required.

Does that clear things up?

isometric fillet.dwg

Genius MaxwellEdison,

I knew i was onto something when i drew that sphere, the sloppy drawing is unforgivable though, cheers for colour coding and your explanation.

Another quick question: how would i draw the intersection if the arc was supposed to go to the top corner, rather then forming the 45 arc as it does here. Draw a cone shape?

Thanks.

Basically the same tactic, although this time all you really need is the bounding circle (magenta). Line it up at the one end and copy/move it to the other where it intersects the outside edge. Then trim and you're done.

isometric fillet.dwg

I'll look at it when i get home, but i think i got it.

Thanks for the quick reply.

Ok I still got a problem after all.

I drew a 3D version of what I was intending to draw initially, the one with he arrow in the file "3D fillet". The one on the right being the first file that you uploaded in 3D.

In the other file i attempted to draw the intersecting point of the two fillets at the corner, rather then the 3 as earlier example. Here is where i'm getting confused; initially i though i was able to construct the intersect arc by dividing the two filleting arcs and projecting the lines across (the blue and the red here) and then draw a spline where they intersect. Looking at it closer i started seeing that the way AutoCad divides the arc is different to the manual way i would have done it, by dividing a circle and projecting the lines, which i can't explain. I would imagine this would have an effect on the accuracy of the intersect arc. The spline didn't even look right to begin with.

I then tried to draw it with an ellipsis (the yellow), this didn't match-up with the spline at all, but looks reasonably accurate as far as i can tell.

Where have i gone wrong?

isometric fillet divide problem.dwg

3D fillet.dwg

Bumped,

Can anyone help, still a bit unsure about meh iso. fillets.