Triangle count is incorrect when above around 2 billion #57884

New Issue

Carlo Andreacchio · 2018-11-17T01:45:26+01:00

Carlo Andreacchio commented

2018-11-17 01:45:26 +01:00

System Information
Ubuntu 17.10

Blender Version
Broken: 2c347ebbba

Short description of error
Triangle count is incorrect when its too large

Exact steps for others to reproduce the error

Get high resolution tree and make it into bounding box mode
create particle plane
increase particle count until the triangles get above 2billion approximately
notice how the number of triangles goes into the negative.

This happens on production scenes --

**System Information** Ubuntu 17.10 **Blender Version** Broken: 2c347ebbba9 **Short description of error** Triangle count is incorrect when its too large **Exact steps for others to reproduce the error** 1. Get high resolution tree and make it into bounding box mode 2. create particle plane 3. increase particle count until the triangles get above 2billion approximately 4. notice how the number of triangles goes into the negative. This happens on production scenes -- ![Selection_079.png](https://archive.blender.org/developer/F5592631/Selection_079.png)

Carlo Andreacchio commented

2018-11-17 01:45:26 +01:00

Added subscriber: @candreacchio

Carlo Andreacchio commented

2018-11-17 02:23:38 +01:00

This is actually a problem on verts and faces aswell, not just tris.

Stephen Swaney commented

2018-11-18 15:38:39 +01:00

Added subscriber: @StephenSwaney

Stephen Swaney commented

2018-11-18 15:38:39 +01:00

Please attach a .blend showing the problem.

This sounds like integer overflow.
A signed integer has a maximum value of roughly 2,000,000,000. Go over that and you get negative numbers.

  - MISSING INFO

Please follow our submission template and guidelines and make a complete, valid bug report, with required info, precise description of the issue, precise steps to reproduce it, small and simple .blend and/or other files to do so if needed, etc.

A guideline for making a good bug report can be found here: https://wiki.blender.org/wiki/Process/Bug_Reports

Marking as "Incomplete" until the requested information/data is provided.

Please attach a .blend showing the problem. This sounds like integer overflow. A signed integer has a maximum value of roughly 2,000,000,000. Go over that and you get negative numbers. - MISSING INFO Please follow our submission template and guidelines and make a complete, valid bug report, with required info, precise description of the issue, precise steps to reproduce it, small and simple .blend and/or other files to do so if needed, etc. A guideline for making a good bug report can be found here: https://wiki.blender.org/wiki/Process/Bug_Reports Marking as "Incomplete" until the requested information/data is provided.

Carlo Andreacchio commented

2018-11-18 22:12:57 +01:00

Probably not the most efficient bug blend, but its there. make sure you have enough ram to open the file (not a problem in blender 2.7)

overflow.blend

Probably not the most efficient bug blend, but its there. make sure you have enough ram to open the file (not a problem in blender 2.7) [overflow.blend](https://archive.blender.org/developer/F5624873/overflow.blend)

Philipp Oeser commented

2018-11-19 12:16:08 +01:00

Added subscribers: @Sergey, @lichtwerk

Sergey Sharybin was assigned by Philipp Oeser

2018-11-19 12:16:08 +01:00

Philipp Oeser commented

2018-11-19 12:16:08 +01:00

Overflow confirmed.

@Sergey: does this have to be changed to long (or whatever) all over the place? DNA_mesh_types etc?

Overflow confirmed. @Sergey: does this have to be changed to long (or whatever) all over the place? DNA_mesh_types etc?

Sergey Sharybin commented

2018-11-19 12:42:21 +01:00

Never use long! It is platform specific and different on different OS/bitnesses. Use uint64_t in the statistics. Doing this in DNA_mesh_types is hell of a lot of work, which will involve modifying all the areas which loops and indices those.

Quite sure avoiding overflow in stats will solve 99% of cases. And quite sure once you've got mesh with more than 2B vertices you'll have other issues.

P.S. Do you expect me to work on this?

Never use `long`! It is platform specific and different on different OS/bitnesses. Use `uint64_t` in the statistics. Doing this in DNA_mesh_types is hell of a lot of work, which will involve modifying all the areas which loops and indices those. Quite sure avoiding overflow in stats will solve 99% of cases. And quite sure once you've got mesh with more than 2B vertices you'll have other issues. P.S. Do you expect me to work on this?

Carlo Andreacchio commented

2018-11-19 12:47:56 +01:00

This isn't to do with one mesh but a scene... I opened our production scenes from blender 2.7 in 2.8 and it's reporting it.

The difference lies with 2.8 counting each particle instance in the tri /vert / face count rather than discounting it entirely.

Not sure who should work on it but it does occur in normal scenes for us.

If any more info is needed please let us know and we will clarify as soon as possible

Carlo

This isn't to do with one mesh but a scene... I opened our production scenes from blender 2.7 in 2.8 and it's reporting it. The difference lies with 2.8 counting each particle instance in the tri /vert / face count rather than discounting it entirely. Not sure who should work on it but it does occur in normal scenes for us. If any more info is needed please let us know and we will clarify as soon as possible Carlo

Sergey Sharybin was unassigned by Philipp Oeser

2018-11-19 13:07:59 +01:00

Philipp Oeser commented

2018-11-19 13:07:59 +01:00

think I checked and me_eval->totloop was overflowing already, but will have a second look...

think I checked and `me_eval->totloop` was overflowing already, but will have a second look...

Sergey Sharybin commented

2018-11-19 13:27:57 +01:00

@lichtwerk if that thing is overflowing, then drawing will not be correct. And the modifiers, or anything. That's very weird and dangerous if that thing is overflown.

Philipp Oeser commented

2018-11-19 13:31:17 +01:00

@Sergey: yep, my bad (will stand in the corner for a while...), was something else overflown, checking this again atm...

Sergey Sharybin commented

2018-11-19 13:42:22 +01:00

@lichtwerk, my bet would be on SceneStats from info_stats.c. Change int to uint64_t would be the first step. Second one would be to ensure correct format in SCENE_STATS_FMT_INT is used.

@lichtwerk, my bet would be on `SceneStats` from `info_stats.c`. Change `int` to `uint64_t` would be the first step. Second one would be to ensure correct format in `SCENE_STATS_FMT_INT` is used.

blender-admin commented

2018-11-19 15:24:32 +01:00

This issue was referenced by cec83e92e6

This issue was referenced by cec83e92e6160adf1e39e0173c77743cb1ff1be7

Philipp Oeser commented

2018-11-19 15:27:07 +01:00

I had a go in D3962

I had a go in [D3962](https://archive.blender.org/developer/D3962)

Philipp Oeser commented

2018-11-21 16:41:19 +01:00

Changed status from 'Open' to: 'Resolved'

Philipp Oeser closed this issue

2018-11-21 16:41:19 +01:00

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Triangle count is incorrect when above around 2 billion #57884