ScrapPeak brush generate spikes/holes -and- strike on other side of a sculpt #37177

New Issue

Sanc Tuary · 2013-10-22T13:45:22+02:00

Sanc Tuary commented

2013-10-22 13:45:22 +02:00

%%%--- Operating System, Graphics card ---
winxp sp3 32bits

- Blender version with error, and version that worked ---

tested in 2.69 RC3 , i can't confirm for the spikes/holes in 2.68a but i could still obtain the brush strokes occuring on both side in that version

- Short description of error ---

When you use the Scrape/Peak brush with Dyntopo enabled , at some level of zoom, you will generate nasty spikes/holes-like topology on the other side of your sculpt, even if you enable "Front face only"

- Steps for others to reproduce the error (preferably based on attached .blend file) ---

The model is simple for reproducing purposes, and displayed in the attached screen001.jpg
Load the attached scrapepeakhole.blend file - With "LOAD UI" enabled - (i used a load factory setting and i prepared the brush, the angle of view and zoom level it makes it easy to reproduce)
click on the Enable Dynamic Topology button and press Z (to switch to wireframe to make it easy for you to see the nasty spike/hole being generated)
If i don't switch to Z personnally i can't generate the nasty holes/spikes but other people on other systems do, but the "sculpt on both side instead of the one we should be sculpting on" still happens.
start making strokes on the whole 3D view, if you don't notice the kind of oddity appearing in the attached screen002.jpg , zoom in and restroke the whole 3D view
zoom out and notice that the strokes have been applied on both side instead of only the side we were sculpting on as shown in the attached screen003.jpg
attached screen004.jpg show that other side in solid display , you can see those odd holes generated better

important note :
the problem was posted on the BA boards here for information with other more complex blend example :
http://www.blenderartists.org/forum/showthread.php?314941-Dyntopo-sculpting-Random-holes-appearing-while-sculpting

showing that it can happen in much less zoomed in situation, for me it happened that i was unable to reproduce the problem from the thread at the example of zoom given, but could if i zoomed in a lot more.

So while in my simpler example blend from this report i have zoomed in a very lot more than what i would use to sculpt, it may be possible for you to reproduce the problem with a less zoomed in version.

Note 2 : i noticed in the Dyntopo test thread of the Blenderartist board that it has been reported that the problem can happen with Multiresolution sculpting, not only with Dyntopo :
http://blenderartists.org/forum/showthread.php?264568-Dyntopo-tests&p=2497061&viewfull=1#post2497061%%%

%%%--- Operating System, Graphics card --- winxp sp3 32bits - Blender version with error, and version that worked --- tested in 2.69 RC3 , i can't confirm for the spikes/holes in 2.68a but i could still obtain the brush strokes occuring on both side in that version - Short description of error --- When you use the Scrape/Peak brush with Dyntopo enabled , at some level of zoom, you will generate nasty spikes/holes-like topology on the other side of your sculpt, even if you enable "Front face only" - Steps for others to reproduce the error (preferably based on attached .blend file) --- * The model is simple for reproducing purposes, and displayed in the attached screen001.jpg * Load the attached scrapepeakhole.blend file - With "LOAD UI" enabled - (i used a load factory setting and i prepared the brush, the angle of view and zoom level it makes it easy to reproduce) * click on the Enable Dynamic Topology button and press Z (to switch to wireframe to make it easy for you to see the nasty spike/hole being generated) If i don't switch to Z personnally i can't generate the nasty holes/spikes but other people on other systems do, but the "sculpt on both side instead of the one we should be sculpting on" still happens. * start making strokes on the whole 3D view, if you don't notice the kind of oddity appearing in the attached screen002.jpg , zoom in and restroke the whole 3D view * zoom out and notice that the strokes have been applied on both side instead of only the side we were sculpting on as shown in the attached screen003.jpg * attached screen004.jpg show that other side in solid display , you can see those odd holes generated better important note : the problem was posted on the BA boards here for information with other more complex blend example : http://www.blenderartists.org/forum/showthread.php?314941-Dyntopo-sculpting-Random-holes-appearing-while-sculpting showing that it can happen in much less zoomed in situation, for me it happened that i was unable to reproduce the problem from the thread at the example of zoom given, but could if i zoomed in a lot more. So while in my simpler example blend from this report i have zoomed in a very lot more than what i would use to sculpt, it may be possible for you to reproduce the problem with a less zoomed in version. Note 2 : i noticed in the Dyntopo test thread of the Blenderartist board that it has been reported that the problem can happen with Multiresolution sculpting, not only with Dyntopo : http://blenderartists.org/forum/showthread.php?264568-Dyntopo-tests&p=2497061&viewfull=1#post2497061%%%

Sanc Tuary commented

2013-10-22 13:45:22 +02:00

Changed status to: 'Open'

Sebastian Koenig commented

2013-10-22 15:49:47 +02:00

%%%Yeah, I noticed that too, but couldn't reproduce or nail it down. Jonathan Williamson said he had it too.
Cool to see this issue nailed down and reported! :)%%%

%%%Yeah, I noticed that too, but couldn't reproduce or nail it down. Jonathan Williamson said he had it too. Cool to see this issue nailed down and reported! :)%%%

Antonis Ryakiotakis commented

2013-10-23 01:15:45 +02:00

%%%Confirmed, and I have an idea about what it might be.

The spikes/holes must be a separate issue than the two-side issue though.

Assigning to self.
%%%

%%%Confirmed, and I have an idea about what it might be. The spikes/holes must be a separate issue than the two-side issue though. Assigning to self. %%%

Antonis Ryakiotakis commented

2013-10-23 01:34:26 +02:00

%%%Indeed they are a different issue. Spikes are fixed in r60900, looking into the sculpt through issue now.%%%

Antonis Ryakiotakis commented

2013-12-18 02:41:48 +01:00

This seems to be a precision issue because we use rays that start too far away from the mesh when using orthographic camera. If this is the case, it is easy to fix by projecting vector to object bounding box. Still I want to dig some more, it seems strange that the front faces are not 'hit' at all.