Problem with scaling and snapping when using Edge constraints

[mikael.blomqvist.88]

When im trying to align a selection by scaling down to zero in the appropriate axis it doesn't work when Edge constraints are turned on. It limits the scaling to a stop which never goes all the way. I get closer by doing it several times but it never completely aligns. When constraints are Off it works perfectly.

I have a similar problem when holding down the v-key (snap to points) and moving a vertex to try and snap while edge constraints are on. It always snaps a distance away from the vertex I'm aiming at. Yet again, it works fine when constraints are off.

I've googled these issues for hours now without finding the solution. I'm thankful for any ideas that might help.

[mikael.blomqvist.88]

Still haven't managed to solve this. I don't know if this is a bug or if it's supposed to behave like this, but I really don't see the reason why if that's the case. So if anyone would be willing to try the two situations I described above and report back here I'd really appreciate it.

[mspeer]

Hi!

I am not able to reproduce this here with Maya 2020.

Please provide an example scene and the exact steps how to reproduce this.

[mikael.blomqvist.88]

Hi! I forgot to mention I'm using Maya 2019. I made a screencast of the problem.
The scene is just a 2x2 plane where I've moved the top three vertices to a slope and the middle lower edge to the right.
In the video I first show how the scale tool aligns the three middle vertices without edge constraints. It works with one simple click and drag - as it should. Next, I try the same thing with edge constraints. As you can see it stops short. In order for it to align I have to repeat the click-drag process at least two times. The number of times necessary seems to vary depending on the topology and/or distance. So I was mistaken in my first post where I said it never completely aligns, it does but it takes several tries.
The final thing I show in the video is the problem with vertex snapping, which is basically the same issue where it stops short and requires at least three attempts to align when using edge constraints.
Also: I noticed that scaling and snapping with edge constraints on works fine as long as the topology is made up of completely horizontal and vertical lines.

[mspeer]

Hi!

Thanks for the video, i can reproduce this behavior here.

As the top vertex is moving in an other direction than the scaling direction (/ axis) it can't reach the same vertical position as the other vertices.

What you can try is to disable "Prevent Negative Scale" which allows for further scaling into the negative range.

It's the same with snapping.

I would call this a limitation, but it should be possible to update the algorithms for a different behavior (maybe as option or replacement)

I recommend to add this to Maya Ideas

Help -> Speak Back -> Ideas for Maya

[mikael.blomqvist.88]

Hello again. Thanks for the reply and for taking the time to test this out.
"Prevent Negative Scale" does work but its a bit fiddly to make the selection align since I have to eyeball it, but it's certainly better than nothing.
So there's no solution for easier snapping with Edge constraints then? Or perhaps another method to working around it other than having to repeat the click-drag process several times?
I will make a post about it in Maya ideas.

[mspeer]

Hi!

I tried moving only the top vertex with Axis Orientation Component + Snapping, however it shows the same problem.

So no, there is no other solution (or at least i am not aware of any other solution).

I recommend to create some helper objects for snapping and alignment or use an other modeling approach.

In this example i would delete the middle edges/vertices and re-create them with the insert edge loop tool at the wanted position, which would result in a straight line and the top edge would be preserved.