(Vertex)-Snapping issues, especially on very large Scenes
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Description

System Information

Win 7 64x (but experienced this issue on Ubuntu as well)
Geforce GTX 560 ti

Blender Version

2.71 (but experienced this issue on older versions)

Descriprion
vertex-snapping in ortographic view is kind of displaced.
usualy its acceptable cause the displacement between snapping-area and in viewport rendered vertex is very minor.
But currently im working on a Scene that is about 5km tall and with objects that huge, vertex snapping cannot find the right vertices for snapping.

Reproducion
go orthograpic view,
draw a uv sphere with dimentions about 5000 units
set near clipping plane 0.10
and far clipping 200000
vertex snapping is hardly possible.

[Cause]
In my opinion snapping just checks the vertex positions in the viewport that they occupy in perspective-mode,
even the user has the orhogaphic view activated. so there appears some displacement.

Workaround
just go to perspective viewport-rendering

Event Timeline

Leonardo Kämpf (monatsend) created this task.Jul 10 2014, 4:42 PM

Leonardo Kämpf (monatsend) raised the priority of this task from to 90.

Leonardo Kämpf (monatsend) updated the task description. (Show Details)

Leonardo Kämpf (monatsend) added a project: BF Blender.

Leonardo Kämpf (monatsend) edited a custom field.

Leonardo Kämpf (monatsend) added a subscriber: Leonardo Kämpf (monatsend).

With such and extreme values you're hitting limitation of single precision floating point datatype. It'll be improved if we switch to double precision, but that's rather enormous project which we're considering TODO still.

Thanks for the report, but we're all we;; aware of such limitations and eventually will solve this by switching to a double precision.

Hi,
thank you for taking time,

But this snapping issue appears in small objects as well, in huge objects this effects is only more extreme.
has this snapping-in-orthographica-mode-issue, in general, to do with rounding errors?

Well, if it appears for small objects and sane clipping, please upload .blend file which demonstrates the issue. That'd help a lot.

Ok maybe i mixed two differend things together

but both are a little bit annoying.

if this would be a bit mor accurate,
this would give me a 10% boost in my workingspeed

snappingIssue.blend506 KBDownload

Can't really reproduce the issue here, snapping works rather fine here.

@Antonis Ryakiotakis (psy-fi), @Bastien Montagne (mont29), mind trying to reproduce the issue?

Well, on that file I can reproduce the issue on the left screen but not on the spheres at the right. The clipping values are so extreme that we are getting zfighting between the wireframe and solid mesh just by zooming though. We usually solve such issues by projecting the ray so that it begins from mesh bound box boundaries instead of the clipping plane, but I seem to remember that we do that already for snapping. If that's the case then I'm afraid this won't be solvable without double precision.

Ok very strange, that the snapping issue's didn't appeare in your systems, cause it was so exteme in mine.
maybe different handling in 64x an 32x.

edit: now im working on the same scene (wher i first sumble uppon this issue) with the same computer. and snapping works fine now.
dayum, I cannot reproduce it even by myself !

But in the blend that i send you , snapping vertices on the sphere in the upper right viewport, is not possible on my ubuntu 14.04 64x and my Win 7 64x

As psy-fi, can only see issue with left part, the spheres snap OK for me (linux64 here)…

Bastien Montagne (mont29) lowered the priority of this task from 90 to Normal.Jul 13 2014, 11:28 AM

Can't reproduce issue with spheres as well.

@Thomas Dinges (dingto), @Martijn Berger (juicyfruit), @Lukas Tönne (lukastoenne) mind trying your luck here? :)

Ah ok, seems i see now what kind of issues monatsend was having with the spheres, needed to zoom out a bit in that views.

But that's exactly the same issue as in the left viewport, too much extreme clipping range, which even confuses OpenGL Z-Buffer. You're also having quite extreme scaling on the object, so all this combined together ends up with a huge floating point precision hell..

Some aspects might be improved by switching to a double precision (which is rather really huge project on it's own),or maybe doing some smarter things for ray intersection (which could only solve snapping issue, leaving all the rest unsolved..)

So afraid we'll consider this a TODO for now, not that trivial TODO even.. Thanks for the report anyway!

Hi,
Its me ... again

sorry for rerolling this report ... again
but now I have the Issue in the same scene, but even if I scaled the object to a appropriate size, I'm not able to snap onto vertices or edges.

When I append just the object to a new Scene, snapping works just fine.

Maybe this isnt the right plce to talk about it, but I already startet a "bug-report" with this topic.

It would be nice if you can find the time to take a look at the file.

sonnentempel7_Issue.blend2 MBDownload

thanks in advance

monatsend on a win 64

Two things:

You need to enable "Snap during transform", Shift-Tab, but perhaps this you already know
You've got "Snap onto itself" disabled, this for sure explains why you snapping to vertices of your mesh doesn't happen

Thank you,
now Im feeling very stupid...

I was so fixated on this problem...
with blender you all doing a great work
have a nice week

monatsend

(Vertex)-Snapping issues, especially on very large ScenesClosed, ArchivedPublicActions

Description

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(Vertex)-Snapping issues, especially on very large Scenes
Closed, ArchivedPublic
Actions