Is it correct that sometimes only intersect 1 (for rendezvous) is shown?

[THX1138]

Sometimes only intersect 1 (orange) is shown and sometimes intersect 2 (magenta) is shown as well. Is this correct behaviour? If so, why can't intersect 2 be shown? Sometimes it comes and goes and I can't figure out a pattern.

[mk1980]

the game will show 2 intersects if the 2 orbits intersect twice (ie. they are in the same plane and the PE of orbit 1 is inside orbit 2 but the AP of orbit 1 is outside orbit 2). if orbit 1 is completely inside orbit 2, only one intersect (or more precisely - one "closest approach" is shown because there is only 1 point where the 2 ellipses are closest to each other

[Guest]

Yeah, no. I know what you are talking about. This is new for 1.1. It's a bug. I hope they fix it on the next release.

[bewing]

I filed a bug report on it a week ago: 

 

[Montag]

You can add a maneuver node with 0 dV change, and the 2nd intersection will likely show up.

[Geschosskopf]

This isn't a bug, it's like @mk1980 said.  It's always been this way.  But folks don't seem to understand what he said, so I'll try to explain it again.

Intersections only show up when your orbit crosses or merges with the target orbit.  If it does this once, you get 1 intersection.  If it does it twice, you get 2 intersections.

Imagine you're in a circular 100km orbit and your target is in a circular 200km, and you've already matched planes.  You create a node and pull the prograde handle so that your future orbit will become an ellipse.  As you add prograde to the node, the opposite side of your post-burn orbit rises toward the target orbit.  When it gets close enough to it, the game will draw a single intersection at the point where the paths are closest together.  This is because there's only 1 place where your orbits are close enough for the routine that draws intersections to trigger.

Now you keep adding prograde to the node, so that eventually your post-burn path crosses the target orbit.  Because your Pe is still inside the target orbit, your future path has to cross the target orbit twice, once on the way up to your Ap, and then back again heading to Pe.  Therefore, you get 2 intersection markers.

[Kerbart]

So what determines when you get only purple markers? Or one and a half set of markers (one showing an intersect, and then a "dangling position of target" marker? With the target apparently at two spots simultaneously, is the fabled Schrödinger rendez-vous?

[bewing]

1 hour ago, Geschosskopf said:

 If it does this once, you get 1 intersection.  If it does it twice, you get 2 intersections.

Except it doesn't currently. Try it. Half of the time if your orbits cross properly, you will still only get one intersect marker. It is a bug.

Yes, of course if your orbits don't cross, then you will only get one. But that's not the issue here.

[Guest]

It's no doubt about it a bug. Behavior changed in 1.1. The second intersect did not used to come and go. You can use KER to validate this. KER can always detect the closest approach, even when the stock system cannot, or does but fails to display on screen for some screwy reason.

 

And it also looks like we need a vote down as well as a vote up just like reddit, because someone voted up the wrong answer because they didn't understand the question.

Edited June 3, 2016 by Otis

[Geschosskopf]

On 6/3/2016 at 11:55 AM, Kerbart said:

So what determines when you get only purple markers? Or one and a half set of markers (one showing an intersect, and then a "dangling position of target" marker? With the target apparently at two spots simultaneously, is the fabled Schrödinger rendez-vous?

You get half a marker if the other half would be more than 1 orbit ahead of your current position.