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Hi Fer and Hendrik:
I know I speak for everyone at the NASS Conference
that we were all very impressed with the Mean Time Cone Gnomon Dial that
you helped Hendrik Hollander to develop. Congratulations to Hendrik
for winning the Sawyer Dialing Prize this year. What a surprise. I
knew of Hendrik for his previous work with etched glass and acrylic dials, but I
don't think anybody else knew of him. It caused a great deal of
interest at the NASS Conference since none of us had ever heard
about Hendrik or his new dial before. We loved the fact that it
looks like a simple ordinary dial with straight hour lines, yet it tells
Mean Time because it has a tilted cone gnomon. Fred kept saying that he
wished that he had thought of it. Now that's a compliment!!! We are
all anxious to read more about it in the next issue of The
Compendium.
Afterwards, Roger Bailey and I discussed the
possibility making a DeltaCAD macro for it with the following user
inputs:
latitude
longitude (for longitude correction)
inclination
declination
apex angle of the cone
size
The macro would produce a drawing of the face and a
sideview drawing of the gnomon.
It would be fun to make one of these
someday.
One question: Isn't it possible to make this
type of dial for any plane (horizontal, vertical, inclining and
reclining)?
Congratulations to you both for coming up with this
new sundial design concept and thanks for the handout you made for
us.
John Carmichael
----- Original Message -----
Sent: Monday, August 21, 2006 11:04
AM
Subject: NASS Conference
Hi John,
Nice to hear from you about the NASS
Conference.
Is your suitcase back home? All worry about these
things.
It was a great pleasure to me to get the chance
to present the Sawyer Dialing Prise to Hendrik
Haollander.
It was a pleasant meeting that day in
july.
What do you think about the new sundial he
develloped? I love the idea and I am glad I could be of some help with
it.
Best wishes, Fer.
Fer J. de Vries
Eindhoven, Netherlands
lat. 51:30
N long. 5:30 E
----- Original Message -----
Sent: Monday, August 21, 2006 7:40 PM
Subject: Fw: ShadowsPro vs. ZW DXFs
----- Original Message -----
Sent: Monday, August 21, 2006 6:02 PM
Subject: Re: ShadowsPro vs. ZW DXFs
Hi Fer:
I just got back from the NASS conference last
night. The airline lost my suitcase!
Anyway, it was a good conference and Fred showed
a photo of you awarding the Sawyer Dialing Prize to Hendrik Hollender.
Your name came up quite frequently during the conference.
Once again, thanks for helping me understand the
DXF problem.
take care,
John
----- Original Message -----
Sent: Thursday, August 17, 2006 1:07
AM
Subject: Re: ShadowsPro vs. ZW
DXFs
John,
Your last sentence was:
-----------
Note that Fer's default sundial dimension
settings in ZW2000 are quite large. Could this be why we don't
see the problem (of irregular lines) with the ZW2000 DXF
drawings?
-----------
In my dxf file the numbers are rounded to 4
decimals as 0.0001 or 123.0001
If you enlarge this with a factor 1000 there
still is 1 decimal.
So there is no problem with enlarging a
pattern.
But in general it is better not to scale up a
drawing.
Use real dimensions or scale down.
Best wishes, Fer.
Fer J. de Vries
Eindhoven, Netherlands
lat. 51:30
N long. 5:30 E
----- Original Message -----
Sent: Wednesday, August 16, 2006
11:34 PM
Subject: Re: ShadowsPro vs. ZW
DXFs
Fer: You're a genius!
And Francois: I beg your pardon!
Fer, I must thank you so much for figuring
out how to fix and explaining the wavy curved line problem.
It's so easy to fix, and makes sense now. It never occured to
me!
The problem is not with Shadows Pro, but with
how I was using it. I incorrectly had used Shadows Pro's
default settings for the size of the gnomon and sundial face. Then
when I put those DXFs into DeltaCAD I scaled them to the sizes I
needed. The wavy lines appeared when I zoomed in and were horrible
when I enlarged the gnomon from the default size of 30mm to the 8
feet required by my project! That was the mistake I made. I
did not know that the default settings produced wavy lines.
I just tested what you told us to do and
you're right! I was able to fix the problem by entering in the
actual correct sundial dimensions into Shadows Pro BEFORE I put it into
DeltaCAD. Doing it this way, as you advised, fixed the
problem! Thanks Fer! And please excuse me Francois for
thinking that Shadows Pro was the cause.
With that in mind, now that we know how to
use Shadows Pro correctly, we should take Fer's advise and remember this
important lesson about making Shadows Pro DXF drawings:
To avoid wavy irregular curved lines
in the DXF drawings, make your original Shadows Pro
drawing using the sundial's actual dimensions or even
larger.
Note that Fer's default sundial dimension
settings in ZW2000 are quite large. Could this be why we don't
see the problem with the ZW2000 DXF drawings?
Anyway, thanks again Fer for figuring out
what was happening, and please pardon me Francois for my
error.
John
----- Original Message -----
Sent: Wednesday, August 16, 2006
12:59 PM
Subject: Re: ShadowsPro vs. ZW
DXFs
Hi John,
The accuracy in Shadows is 0.1 mm in the
dxf file as Francois wrote.
For a small drawing on screen, in which you
see the complete dial, this accuracy is too low for the dxf file and the
datelines in Deltacad look bad.
This is to overcome by the following
procedure.
In Shadows always start with drawing the
sundial you want as a large one by choosing large
dimensions.
You only see a part of the dial on
screen.
Then make a dxf file of it.
Scale it back to the wanted dimensions in
Deltacad and the lines are fine.
So it is right to say that for large dials
the lines are fine, but they are bad for small dials.
Best wishes, Fer.
Fer J. de Vries
Eindhoven, Netherlands
lat. 51:30
N long. 5:30 E
----- Original Message -----
Sent: Wednesday, August 16, 2006
8:31 PM
Subject: Re: ShadowsPro vs. ZW
DXFs
Hello Francois:
Thank you for answering my letter about
the wavy curved lines seen on DXF files made from Shadows Pro.
Hopefully in a future version you can fix this.
One thing you said does not make sense to
me. You wrote:
"The only case where the accuracy could
be a problem is if you draw a very small handheld
sundial."
It seems to me that just the opposite
happens. I noticed the irregularity problem with curved
declination lines when I was creating a very large sundial, not a
small one. Since the wavy irregularities show up only when you
zoom in and magnify the drawing, they are more visible on large
sundials not small ones. Does that make sense or am I not
understanding you?
But except for that wavy line problem, I
just want to say that I love the rest of Shadows Pro. When a
client comes to my studio, they love seeing the animated shadow
feature on my computer. I show them how the shadow will move on
their sundials before I make them. Also, I see that you have
incorporated Google Earth for finding latitudes and longitudes.
And there are many other nice little additions you have
made.
John
----- Original Message -----
Sent: Wednesday, August 16,
2006 10:51 AM
Subject: Re: ShadowsPro vs. ZW
DXFs
Hello all
In Shadows Pro, coordinates are rounded
to 1/10 of mm. This should be accurate enough for most applications.
But when you zoom a drawing you can see broken lines as their ends
are on a 0.1 mm grid. This is true with DXF and WMF exported
drawings.
The only case where the accuracy could
be a problem is if you draw a very small handheld
sundial.
This rounding operation comes from
early versions of Shadows and I will probably remove it in a
future version to avoid such aesthetic problems.
Regards
François Blateyron
----- Original Message -----
Sent: Sunday, August 13, 2006
5:17 PM
Subject: Re: ShadowsPro vs.
ZW DXFs
John,
Thanks for your examples that show the
differences in the sundial lines in
several programs.
It is
to my opinion a matter of number of points in a line and
rounding
numbers.
If a sundial line is a straight line,
which is known of course, I calculate
in ZW2000 only 2 points
and by that in the computer the line also is
very
straight.
A curved line is calculated as a series of
short lines and saved as a
"polyline".
In Autocad this is a
single line, in Deltacad however still a series of
short
lines.
In the Deltacad macro it is a "spline" which perhaps
is the best.
You also can select it as a single line.
Has
Deltacad an option to convert a series of short lines into a
"spline"?
I couldn't find it, nor the word
"polyline".
In ZW2000 a curved line can be calculated in
two accuracies.
One point for every third day or for every
day.
The default always is every third day. (Less points,
smaller file.)
See option left down in the input
screen.
Usual you don't need this extra option.
Well,
any program has its own advantages and disadvantages by what
the
programmer has choosen.
The same is due for the Cad
programs you use.
Best wishes, Fer.
Fer J. de Vries
Eindhoven, Netherlands
lat. 51:30
N long. 5:30 E
----- Original Message -----
Sent: Saturday, August 12,
2006 7:12 PM
Subject: ShadowsPro vs. ZW
DXFs
Hello all who use a CAD
program (cc. Francois Blatyeron):
I just noticed a big difference in
the sundial DXF drawings produced by Shadows Pro and
ZW2000.
When making a sundial drawing using
Delta Cad I have always either used a DC macro or have imported
a DXF file of the drawing from ZN2000. Recently I
upgraded the Shadows free version to Shadows Pro so that I
could make DXF files and use the other great new features that
Shadows Pro offers. (The free version does not allow you
to make DXF files).
I immediately noticed a problem
with the DXFs produced by Shadows Pro. If you open a
Shadows Pro DXF file in DeltaCAD and zoom in on the curved
declination lines, you will see that, they are
composed of little straight line segments that form wavy
irregular curves, unlike the nice smooth curves that ZN2000
produces. ZN2000's DXF's curved lines are
also composed of short straight line segments, but
they have a much smoother curve than the declination
lines made by Shadows Pro's DXF.
Another difference I noticed was in
the equinox straight lines. The ZN2000 equinox line is
just one long straight line, but the Shadows Pro equinox
line is lots of tiny straight lines. (makes editing more
difficult)
If you look at a Shadows Pro DXF
sundial drawing in DeltaCAD without zooming in it looks ok, but
when you zoom in, the curved lines look horrible. This
could cause your final sundial to look the same if, for example,
an engraving machine uses a DXF made from a Shadows Pro
drawing.
Maybe Francois can fix this
problem?
John
p.s. Also, in Shadows
Pro, while drawing a horizontal dial, in the "Sundial" tab at
the top of the page, I can not get the "Declination Lines
Option" pop up page to function. The page comes
up with all the available options, but nothing on the page
functions.
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