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IDProjectCategoryView StatusLast Update
0001762SkyChart1-Softwarepublic18-10-03 09:51
ReporterMichael Lewinger Assigned ToPatrick Chevalley  
Status confirmedResolutionopen 
Product Version4.1 SVN 
Target Version4.4 
Summary0001762: Animation rendering for milky way slow

I like to produce movies such as this one (giving due credit, BTW): I use animation settings such as HD720, 15 sec between frames, and the overall result is very pleasant.

When the Milky Way is displayed in "fill" mode, frame rendering takes between **5 and 10 times** longer than when it is not displayed, or displayed in line mode. Obviously, animation takes much longer, but I imagine that people using CC for controlling telescopes suffer more than I do :)
TagsNo tags attached.



17-09-01 12:42

reporter   ~0003969

BTW, I have noticed few overlapped labels on your video (around 4:00). Perhaps that happens for some settings or particularly when make a video, however that is not welcome.

Can you be more specific about parameters?

Michael Lewinger

17-09-03 07:01

reporter   ~0003970

Hi. I am not sure about the 04:00 overlapped labels, or what did you mean by "not welcome". I hope that I didn't make a bad impression on the Sky Chart program or its usage.

I use animation frames - 30 frames/sec, 15 secs interval between frames (x450 speed). When the milky way is displayed as fill in", such as in the movie shown, rendering of a 1 min movie (0000904:0001800 frames) takes a few hours. On the same computer, when milky way is presented as line only, it takes between 20 to 30 mins to produce the same amount of frames - about 10 times faster.


17-09-03 09:12

reporter   ~0003971

It is just a note for Patrick to take a look additionally, nothing else. Overlapped labels are not welcome on the map. Attached screen shot with problematic parts.
Overlapped labels on video.JPG (64,033 bytes)   
Overlapped labels on video.JPG (64,033 bytes)   

Michael Lewinger

17-09-03 09:33

reporter   ~0003972

Parameters for animation rendering
parms1.PNG (15,986 bytes)   
parms1.PNG (15,986 bytes)   

Michael Lewinger

17-09-03 09:33

reporter   ~0003973

Parameters for milky way display
parms2.PNG (25,420 bytes)   
parms2.PNG (25,420 bytes)   

Patrick Chevalley

17-09-11 08:53

administrator   ~0003974

Yes this milky way drawing is slow and this is why it is not activated by default even if it is nicer.

But it is probably possible to optimize the drawing speed, maybe by preparing in advance the milkyway "pixels" of different brightness instead of computing each one.

Sasa, the label overlap are because in Setup/Display, "Automatically optimize the labels placement" if off.
This is recommended for the animation to avoid "dancing" labels as the optimization algorithm is not stable and the label can jump from one side of the object to another between each frame.

Maybe a solution is to have an option to only suppress overlapping labels without trying to change their position.


17-09-17 11:09

reporter   ~0004023

Perhaps it is established general order for showing labels: constellation name, planets... stars, nebula? Or similar...

Is true, then perhaps is easy to keep list of shown objects started from first frame and add new only if do not overlap, within one second and then reset it when start second second of the video? Or perhaps within 250ms video duration...

That should work fine either when zoom or move.

Just a though.

Michael Lewinger

17-09-17 11:12

reporter   ~0004024

Much appreciated.
I suggest to try to reduce label size when overlapping, to a minimum of readability (4 - 5 px ?). Or use different colors.

Issue History

Date Modified Username Field Change
17-08-31 14:31 Michael Lewinger New Issue
17-09-01 12:42 Sasa Note Added: 0003969
17-09-03 07:01 Michael Lewinger Note Added: 0003970
17-09-03 09:12 Sasa File Added: Overlapped labels on video.JPG
17-09-03 09:12 Sasa Note Added: 0003971
17-09-03 09:33 Michael Lewinger File Added: parms1.PNG
17-09-03 09:33 Michael Lewinger Note Added: 0003972
17-09-03 09:33 Michael Lewinger File Added: parms2.PNG
17-09-03 09:33 Michael Lewinger Note Added: 0003973
17-09-11 08:53 Patrick Chevalley Assigned To => Patrick Chevalley
17-09-11 08:53 Patrick Chevalley Status new => confirmed
17-09-11 08:53 Patrick Chevalley Target Version => 4.2
17-09-11 08:53 Patrick Chevalley Note Added: 0003974
17-09-17 11:09 Sasa Note Added: 0004023
17-09-17 11:12 Michael Lewinger Note Added: 0004024
18-10-03 09:51 Patrick Chevalley Target Version 4.2 => 4.4