I'm not sure if people still use EPSpline to make lathe and prism objects, but I
found the inability to take a photo or a sketch and actually trace around it
pretty limiting.

I found Auto Hot Key has a script that allows you to take a window, make sure
it's "Always on Top", make it transparent (0 - 255), and then set it to
"click-through" so that you can work with the window underneath it.

http://www.autohotkey.com/board/topic/53249-transparent-andor-always-on-top/

Opening an image file, I can use AutoHotKey as a transparent mask so that I can
use EPSpline to trace "under" the image outline.

Hope that's a useful trick for folks.

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A few things I'm noticing about this as I learn how to use it:

1.  I get "Only /EDIT and /RENDER may be passed to previous instance"

2.  If I close POV-Ray and launch with EPSpline, it then wipes out my previously
opened tabs.  This makes my inner raytracing code cry isosurface tears.  :(

3.  The lathe object is upside down when rendered from the .inc file, as opposed
to when it gets rendered via the temporary files generated by EPSpline

4.  The prism object is 90deg from how it was rendered when called by EPSpline,
and since it isn't "at the origin", rotate and scale are fraught with trouble.

Any tips from experienced users?

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Data imported into Excel and plotted with X,Y scatter plot with smooth lines.

Since the chart auto-updates with each cell edit, this looks useful for
hand-editing spline data.   I can also see I have an errant point that's messing
up my lathe...

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Attachments:
Download 'exceldata.png' (21 KB)

Preview of image 'exceldata.png'

On 09/07/2014 03:16 PM, Bald Eagle wrote:
> A few things I'm noticing about this as I learn how to use it:
>
> 1.  I get "Only /EDIT and /RENDER may be passed to previous
> instance"

Those options are returned by MSWindows with the command when MSWindows
is queried for the 'handler' for *.pov files (i.e., pvengine). They were
previously left on the command line; They are now stripped off.
(They seemed to work with POV-Ray 3.6, and seem to cause trouble with
3.7, as I recall.)

>
> 2.  If I close POV-Ray and launch with EPSpline, it then wipes out my
> previously opened tabs.  This makes my inner raytracing code cry
> isosurface tears.  :(

I was not aware of that; I only do some portable software testing under
MSWindows, I don't actually use it, so there is much about the MSWindows
version of POV-Ray that I cannot anticipate.

The gist of the problem is that like most MSWindows programs, MSWindows
POV-Ray is not designed to be used as a child utility (the Unix version
was probably not "designed" with that in mind either, but works fine in
that way as its interface is simpler, completely without an editor, and
not designed for interactive use). Using MSWindows POV-Ray as a preview
is a hack, a convenience.  With the new license a hacked POV-Ray could
be included *in* Epspline, albeit without an editor and using a display
surface provided by Epspline. *I have no intention* of doing that.

It would be very nice if MSWindows POV-Ray had options that would make
it simply render (and display) a files argument. I won't presume to ask
the devs to add features, but if some options become (or are -- I could
have missed them) available for that, then epspline can use those
options if they are added to the command in the Edit->Preferences dialog.

>
> 3.  The lathe object is upside down when rendered from the .inc file,
> as opposed to when it gets rendered via the temporary files generated
> by EPSpline
>
> 4.  The prism object is 90deg from how it was rendered when called by
> EPSpline, and since it isn't "at the origin", rotate and scale are
> fraught with trouble.
>
> Any tips from experienced users?

I covered this in the docs; select Help->"Help Contents" and then go to
section 2.4 Useful Transforms.  I hope it is comprehensible: I am not a
documentation writer (much tougher than coding).

-Ed

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Ed Hynan <no_### [at] examplecom> wrote:
> On 09/07/2014 03:16 PM, Bald Eagle wrote:
> > A few things I'm noticing about this as I learn how to use it:
> >
> > 1.  I get "Only /EDIT and /RENDER may be passed to previous
> > instance"

I found a way to prevent that for now:
Uncheck "Keep Single Instance" under OPTIONS.
http://www.povray.org/documentation/view/3.6.0/684/

I think somehow it ought to be possible.  Under OPTIONS there is the Drag'N'Drop
Destinaation - where one can choose Editor or Renderer.

Under Render there is "Select File and Render"

> > 2.  If I close POV-Ray and launch with EPSpline, it then wipes out my
> > previously opened tabs.

I'm guessing that as long as the tabbed instance is closed last, the tabs will
be preserved.

> It would be very nice if MSWindows POV-Ray had options that would make
> it simply render (and display) a files argument. I won't presume to ask
> the devs to add features, but if some options become (or are -- I could
> have missed them) available for that, then epspline can use those
> options if they are added to the command in the Edit->Preferences dialog.

See above - Are these 2 different things?
Maybe clipka can throw some light on this.

> > 3.  The lathe object is upside down when rendered from the .inc file,
> > as opposed to when it gets rendered via the temporary files generated
> > by EPSpline
> >
> > 4.  The prism object is 90deg from how it was rendered when called by
> > EPSpline, and since it isn't "at the origin", rotate and scale are
> > fraught with trouble.


> I covered this in the docs; select Help->"Help Contents" and then go to
> section 2.4 Useful Transforms.  I hope it is comprehensible: I am not a
> documentation writer (much tougher than coding).
>
> -Ed

Right on.  I guess that didn't sink in the first 2 times I read it.  :\

Thank you for taking the time to create and  keep developing this!

I suppose what I found odd, being new to using this, was that the temporary
files that get generated automagically render things how I'd want and expect
them, but that the include file doesn't include that transform, and that there's
not an export option for saving a copy of the temp file as a scene.
My thought is just that - the work's already done - why tell the user to REDO
it?  Just save the .pov file with the proper SDL already implemented.

I see that you have a lot of "constants" in the generated include file.
I was able to derive MOST of those on my own to see what was going on, but some
remain mysterious.  Taking all of the Y-values (and Z, in the case of the prism)
and subtracting them from the MAX of the combined X&Y's of the lathe and prism
flipped it upside down.That might be an option for generating the include file
so that it's closer to "native" - no transforms needed.  It also drops the base
down to zero.
Maybe just a "flip vertical" option one could do before export.

Would it be possible to allow viewing space to the left of -X values?  I had a
control point that hung out back there.

Would it possible to select a point I'd like to be ON the axis, and then SNAP
the whole object to the y-Axis based on that point's X-value?

I had some trouble with a few extra points floating around - but I couldn't see
them (so I could delete them) until I plotted them out.  Would it be possible to
select a point and then step forwards or backwards along the spline so one could
follow the points "in order"?

Just some food for thought and suggestions.
Again - great work - well beyond my present skill set.

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On 09/09/2014 11:27 AM, Bald Eagle wrote:
> Ed Hynan <no_### [at] examplecom> wrote:
>> On 09/07/2014 03:16 PM, Bald Eagle wrote:
>>> A few things I'm noticing about this as I learn how to use it:
>>>
>>> 1.  I get "Only /EDIT and /RENDER may be passed to previous
>>> instance"
>
> I found a way to prevent that for now:
> Uncheck "Keep Single Instance" under OPTIONS.
> http://www.povray.org/documentation/view/3.6.0/684/

Good! I just spotted that too.

>
> I think somehow it ought to be possible.  Under OPTIONS there is the Drag'N'Drop
> Destinaation - where one can choose Editor or Renderer.
>
> Under Render there is "Select File and Render"
>
>>> 2.  If I close POV-Ray and launch with EPSpline, it then wipes out my
>>> previously opened tabs.
>
> I'm guessing that as long as the tabbed instance is closed last, the tabs will
> be preserved.

Something to try: epspline Edit->Preferences dialog, 'POV-Ray Options' 
field, append /NORESTORE (I'm not certain it'll help but looks worth a try).

>
> Thank you for taking the time to create and  keep developing this!
>
> I suppose what I found odd, being new to using this, was that the temporary
> files that get generated automagically render things how I'd want and expect
> them, but that the include file doesn't include that transform, and that there's
> not an export option for saving a copy of the temp file as a scene.
> My thought is just that - the work's already done - why tell the user to REDO
> it?  Just save the .pov file with the proper SDL already implemented.

Well, for each individual object, e.g. "foo", the exported file has a 
macro foo_NORMAL_TRANSFORM that scales the object to one unit in the 
greater dimension, centers the object at <0,0,0>, and does the inversion 
to expected orientation.  That macro can be used in SDL, or
before including, declare foo_USE_NORMAL_TRANSFORM and that will enable 
a transform { foo_NORMAL_TRANSFORM } within a conditional within the 
object declaration.

What is missing is a similar macro for all the objects of a type (prism 
or lathe) collectively that could be applied to a union or merge.  Maybe 
next release.

>
> I see that you have a lot of "constants" in the generated include file.
> I was able to derive MOST of those on my own to see what was going on, but some
> remain mysterious.  Taking all of the Y-values (and Z, in the case of the prism)
> and subtracting them from the MAX of the combined X&Y's of the lathe and prism
> flipped it upside down.That might be an option for generating the include file
> so that it's closer to "native" - no transforms needed.  It also drops the base
> down to zero.
> Maybe just a "flip vertical" option one could do before export.
>
> Would it be possible to allow viewing space to the left of -X values?  I had a
> control point that hung out back there.
>
> Would it possible to select a point I'd like to be ON the axis, and then SNAP
> the whole object to the y-Axis based on that point's X-value?
>
> I had some trouble with a few extra points floating around - but I couldn't see
> them (so I could delete them) until I plotted them out.  Would it be possible to
> select a point and then step forwards or backwards along the spline so one could
> follow the points "in order"?
>
> Just some food for thought and suggestions.
> Again - great work - well beyond my present skill set.

Well, there's no limit to good ideas, but there is a severe limit on the 
time I can spend on epspline.  It was began to scratch an itch and 
released in the hope it is helpful, but it brings no income (which I 
happen to need very much).

-Ed

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On 09/07/2014 01:28 PM, Bald Eagle wrote:
> I'm not sure if people still use EPSpline to make lathe and prism objects, but I
> found the inability to take a photo or a sketch and actually trace around it
> pretty limiting.

A short four months after your post, and quite a long time after the 
need became obvious, a background image feature has been added to 
Epspline with release 0.0.4.4.

See http://agalena.nfshost.com/b1/epspline-prism-and-lathe-editor/

Hope it helps,
Ed Hynan

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