After I started this Blog, thankfully, I'm getting more feedback than i expected, and I love it.
A week ago, I posted about 3-point Circle. And I got a response from Dr. Mark.
I think the bottom line of his idea is reducing complicated formulas, and placing proper location.
Like i said at this post, I hate formulas too. :-) And he is right about the placing part. I just ignored it at the last post.
Dr. Mark's Idea is quite impressive. But I thought it there must be a simpler way. (I think there're always easier or simpler ways when use Revit)
Here is my solution.
I didn't use any of formulas except '='. I just used the feature of Host Point by Intersection.
Thanks again Dr.Mark.