The persistent cache feature is a work-in-progress. Not in nightly builds yet.

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MichaelAtOz' wrote

Ok, I´ll wait. But, the cache behavior is going to be the exactly the same
in command-line and GUI, am I right? Thanks!

Whosawhatsis wrote

This totally explains why the "Viewport rotation" method did not update the
view :-) Thanks!

JordanBrown wrote

Ok, I´ll do!

JordanBrown wrote

Sure, but this is how a turn table is expected to behave :-)

JordanBrown wrote

Yes, I´ll try to explain it better here, sorry :-)

When I generate the snapshots from GUI there is no problem, the turntable
works as expected (both ways, rotating either the object itself or the
camera).

// Viewport rotation
$vpr=[90,0,-$t*180];
echo("vpr=",$vpr,"vpt=",$vpt,"vpd=",$vpd);
render() mymodel();

The problem arises when I run the same script from the command-line:

#> OpenSCAD-2021.01-RC6-x86_64.AppImage --animate 36 ViewRender.scad

Then, to obtain the same expected behavior I have to explicitly set the view
port distance ($vpd) to some manually adjusted distance, e.g. $vpd=5. If I
do not add this value to the code, then the views appear empty since the
$vpd seems to be set to some very high distance (i.e. 500) by default:

ECHO: "vpr=", [90, 0, 0], "vpt=", [0, 0, 0], "vpd=", 500

Conversely, the same $vpd-less script works perfect from GUI. It seems that
if the GUI is not used, then the $vpd is not appropriately set. May this be
a bug? Any workaround?

Note that for my turntable application the camera must be rotating while
maintaining a constant distance to the object. The $vpd must be maintained
from first to last frame of the animation, but at the same time must be set
automatically to fit the whole object. If the view is fitted to the object
for each frame, this will cause an annoying "zoom in & out" effect. This
latter effect happens if using the "Explicit rotation" approach form
command-line but not from GUI.

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The persistent cache feature is a work-in-progress.

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Yes that is the default for the GUI as well. You have to click on ViewAll
to set it appropriately for your object. On the command line --viewall does
the same.

On Sat, 23 Jan 2021 at 12:34, Michael Marx michael@marx.id.au wrote:

nophead wrote

That is what I though. I tried --viewall option in some of my past tests but
since it did not work I removed it from the command line options (to avoid
adding noise to the discussion :-)... but I was wrong...this may be the key
point.

The --viewall option does not work from command line, at least not for
OpenSCAD-2021.01-RC5-x86_64 and OpenSCAD-2021.01-RC6-x86_64 versions:

#> OpenSCAD-2021.01-RC6-x86_64.AppImage --viewall --animate 36
ViewRender.scad

As you can check, the $vpd remains 500, with or without --viewall option.

SCRIPT CODE:
$vpr=[90,0,-$t*180];
echo("vpr=",$vpr,"vpt=",$vpt,"vpd=",$vpd);
render() mymodel();

OUTPUT:
ECHO: "vpr=", [90, 0, 0], "vpt=", [0, 0, 0], "vpd=", 500

Would this be a bug related to --viewall behavior in command-line tool or am
I doing something wrong?

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And generates this warning with --viewall which explains
what's happening:

WARNING: Viewall and autocenter disabled in favor of $vp*

ciao,
Torsten.

On 1/23/2021 4:13 AM, Vigardo wrote:

So, as you noted, you can either rotate the model, or move the camera.

If you want to simulate a turntable, you'd rotate the model while
keeping the camera in the same place.  Note that the axes stay fixed.

rotate($t*360) cube(10, center=true);

wanted.  You probably don't want --viewall, because for a non-trivial
model it'll probably zoom in and out to make the various views of the
model fit into the viewport.  (Or, alternatively, you could have the
model set $vpr/$vpt/$vpd and lock the viewpoint in place.)

If you want to simulate flying the camera around the model, you'd move
the camera while leaving the model in the same place.  Note that the
axes move, because the camera is moving relative to them.

$vpr=[80,0,360*$t];
$vpd=140;
$vpt=[0,0,0];
cube(10, center=true);

Here you would not want to use --camera or --viewall from the CLI,
because the model file is completely controlling the camera.

What values would you want for $vpt/$vpr/$vpd or, alternatively, for
--camera?  Probably simplest is to first not set up the camera, use
the interactive controls to put the camera where you want it, and then
read the values off the "Viewport" line at the bottom of the window. 
You can also use the "Copy viewport ..." options from the Edit menu.

tp3 wrote

You´re absolutely right. I miss that warning, I´m sorry!

JordanBrown wrote

This is exactly what I´m trying to. However, if I keep the camera fix and
rotate the model, the zoom in and out issue happens. Both using or not
--viewall option. Conversely, if I keep the model fix but rotate the camera
around it, then I have to manually set the $vpd variable... which is not
possible (see next)

JordanBrown wrote

Unfortunately, your approach is not possible for my application. Let me tell
you more. I´m developing some web server that is intended to run OpenSCAD
(server side), so automation and CLI are mandatory. Sorry, perhaps I should
have told this before.

I already figured out a quite dirty workaround to create the turntable... I
used an awk script that parsed the an OpenSCAD generated STL file to dump
its boundary box and from it I can roughly estimate $vpd... But I don´t like
this solution since it slows down even more my workflow. The way OpenSCAD
defines the appropriate camera zoom using the "View All" seems much better.

How would I tell OpenSCAD (from CLI) to use and keep fixed the camera "View
All" parameters?

Perhaps adding a "--viewall_zero" option to initialize all view parameters
at $t=0 (i.e. for the first frame), and then let the user choose which $vp*
parameters to update via code?

Any better alternative?

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I always use --autocenter with --viewall on the command line to get the
camera looking at the object and scaling it to fit. I haven't tried the
command line animation yet. If it recomputes the camera setting per frame I
could that would be a problem. In the GUI you do it first and then start
the animation. It needs to match that.

On Sat, 23 Jan 2021 at 17:32, Jordan Brown openscad@jordan.maileater.net
wrote: