I could swear I used to do this, but I could also be mistaken.
Is it possible to place a half or quarter ellipse tangent to two lines?
I would suggest possibly using the Tangent Snap may be effective in performing this operation.
Snap Mode Toolbox
RegardsAndrew BellTechnical SupportBentley Systems
Andrew, I am aware of the Tangent snap. It doesn't work for half or quarter ellipses - go ahead and try it.
When I place an arc, I have the option to place it "Start, End, Mid" which allows me to snap tangent to the first line and tangent to the second line. This gives me a dynamic arc that I can "pull" about to get the arc I want. I use this often to create an arc that approximates a line string that looks like an arc, but is a bunch of tiny segments around a corner.
There are no options - none - for placing a quarter or half ellipse. And the snaps don't work in the same way.
The first prompt for a quarter ellipse is "enter one end of the ellipse quarter". Right here, I know I am in trouble. I don't know the specific point for the end of the ellipse. I only know that I want the ellipse tangent to this element over here. I can use the tangent snap if I like, but the point accepted does not save the tangency constraint. It only uses the location, not any tangency.
The next prompt asks "enter point on axis". This is essentially looking for the center point of the ellipse. I don't know that, because i am looking for something more dynamic (like the arc). But I can enter a point, just to move on with the exercise.
The third prompt is "enter endpoint". I do have a semi-dynamic element, fixed at the first point and the "center" I chose. At this point, I can't use the tangent snap. It's not allowed. I have the little "no" symbol over the top of what would be my snap.
I don't use this tool often, and I can see why. I hope I am missing something - some step, some setting, getting the prompts wrong?Perhaps I am remembering the tool wrong and it was never possible to create tangent half/quarter ellipses and I did something else instead...
MaryB
Power GeoPak 08.11.09.918Power InRoads 08.11.09.918OpenRoads Designer 2021 R2
Here's a manual animation showing how a constrained Ellipse with a tangent point on each line can yield different alignments of the Major Axis
Excellent demo of constraints!
Regards, Jon Summers LA Solutions
Jon Summers said:Excellent demo of constraints!
That wasn't created in MicroStation I should probably add, before anyone might get the wrong idea.
thats a crying shame .. it looked so good...
Lorys
Started msnt work 1990 - Retired Nov 2022 ( oh boy am I old )
But was long time user V8iss10 (8.11.09.919) dabbler CE update 16 (10.16.00.80)
MicroStation user since 1990 Melbourne Australia.click link to PM me
The new constraints in that arrived in CONNECT possibly allow you to do the same, but as they aren't part of V8i I can't test them, and from what I recall reading previously, constraints were nowhere near in a finished state.