Plots misaligned and distorted at high levels of zoom

benjaminjeliot commented 4 years ago

Describe the bug

At high levels of zoom, the filled boundary plot and the mesh plot become misaligned. Panning the filled boundary plot is smooth, but the mesh plot 'jumps' around.

When objects with very different scales are in view, the filled boundary for small cells moves smoothly while large cells 'jump' about. This can lead to regions that are erroneously drawn as overlapping.

A user found this issue due to numerical artefacts in their output which are many orders of magnitude larger that the main geometry.

Helpful additional information (Please click check boxes AFTER submitting ticket)

[ ] Did VisIt crash?
[x] Did you get wrong results?

Impact

[ ] High - User productivity significantly degraded
[x] Medium - User productivity partially degraded
[ ] Low - User productivity trivially degraded

Likelihood

[ ] High - occurrence is not specific to platform, data, config, a combination of operators, queries, etc.
[x] Medium - neither low nor high likelihood
[ ] Low - occurrence is specific to combination of multiple factors such as configuration, data, platform, etc.

To Reproduce

Steps to reproduce the behavior.

Open the attached zoom_arrows.vtu VTK data set zoom_arrows.vtu.zip
Create a FilledBoundary plot and a Mesh plot
Keep zooming in at the point of the arrow
Eventually see the plot starts to look weird and the zoom 'jumping' about

Plot of the zoom_arrows.vtu data set in VisIt 3.0.2:

zoom_arrows_3_0_2

Expected behavior

The expected behavior is that it should be possible to zoom in smoothly on the mesh data to very high levels of zoom. The expected behaviour is like that in VisIt 2.13.2.

Plot of the zoom_arrows.vtu data set in VisIt 2.13.2 as comparison:

zoom_arrows_2_13_2

To Reproduce

Additionally, to reproduce the issue with very differently sized cells in view:

Open the attached more_zoom_arrows.vtu VTK data set more_zoom_arrows.vtu.zip
Create a FilledBoundary plot and a Mesh plot
Keep zooming in at the point of the arrow
Eventually see the plot starts to look weird and the zoom 'jumping' about

For the differently sized cells issue: more_zoom_arrows.vtu.zip

Plot of the more_zoom_arrows.vtu data set in VisIt 3.0.2:

more_zoom_arrows_3_0_2

Expected behavior

The expected behavior is that it should be possible to zoom in smoothly on the mesh data to very high levels of zoom. Panning at high show not lead to cells erroneously overlapping. The expected behaviour is like that in VisIt 2.13.2.

Plot of the more_zoom_arrows.vtu data set in VisIt 2.13.2 as comparison:

more_zoom_arrows_2_13_2

Attachments

Here is is VTK data set that can be used to reproduce the issue: zoom_arrows.vtu.zip
Here is a second data set that can be used to reproduce the issue: more_zoom_arrows.vtu.zip

Desktop

CentOS 7.7
VisIt Version: 3.0.1 and 3.0.2
- Plots made using visit3_0_2.linux-x86_64-rhel7.tar.gz and visit2_13_2.linux-x86_64-rhel7.tar.gz binaries from VisIt downloads page

biagas commented 4 years ago

To rule out view issues, I decided to try only 1 plot type at a time.

I took zoom_arrows.vtu, created a Filled Boundary plot only, and used rubber-band zoom until there was just the green box and arrows as shown:

zoom_fb_only0000

Then I used the middle mouse button to incrementally zoom in and out, and the transitions were smooth.

When I switched to a mesh plot with opaque mode On and Red in color, the plot jumps around as described by Benjamin.

So, the problem is most likely due to changes made during the VTK8-update in how Mesh plot is handled.

Assigning to myself since I made those changes to the Mesh plot.

biagas commented 4 years ago

Subset plot of Domains, PC plot also exhibit the problem.

visit-dav / visit