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From: Bald Eagle
Subject: Counting gear teeth with POV-Ray
Date: 8 Jun 2017 11:50:01
Message: <web.593939a97ee89277c437ac910@news.povray.org>
I managed to work out:
1. photograph gear on contrasting background
2. crop, convert to heightfield
3. take a slice
4. use trace to measure the width of the gear
5. make an educated guess about number of teeth
6. use trace to take at least twice that number of samples around the perimeter
7. use a change in the direction of the measurement, compared to the radius
determined in (4) to increment the counter

preliminary results so far:

RA0-1179 (69 teeth)
counted 69 teeth

RU6-0190 (193 teeth)
http://www.sunworth-tec.com/productshow.asp?id=1270
counted 192 teeth

I may just need to take more samples.  But that's as far as I got before I hit
the sack.


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From: Bald Eagle
Subject: Re: Counting gear teeth with POV-Ray
Date: 8 Jun 2017 11:55:01
Message: <web.59393a1ea250e006c437ac910@news.povray.org>
larger gear:


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From: Bald Eagle
Subject: Re: Counting gear teeth with POV-Ray
Date: 8 Jun 2017 12:05:00
Message: <web.59393ccda250e006c437ac910@news.povray.org>
One thing I realized about this when contemplating further refinements, and
comparing and contrasting this method with the image-processing based method in
Mathematica, is that the heightfield-slice method gives very nice imperfect
gears that would be ideally suited for objects in scenes where the imperfections
are actually a desired attribute, since they avoid that perfect, "plastic,
computer-generated" look.

This would be a nice way to utilize photos of gears online for a scene.
Say, of and orrery, or the Antikythera mechanism....

:D


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From: Stephen
Subject: Re: Counting gear teeth with POV-Ray
Date: 8 Jun 2017 12:51:54
Message: <5939486a$1@news.povray.org>
On 6/8/2017 12:50 PM, Bald Eagle wrote:
> larger gear:
>

Hmm! I make it 193 teeth, counting on my fingers.
If there is a discrepancy it is about 240° clockwise from TDC.


-- 

Regards
     Stephen


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From: Stephen
Subject: Re: Counting gear teeth with POV-Ray
Date: 8 Jun 2017 15:25:26
Message: <59396c66$1@news.povray.org>
On 6/8/2017 1:51 PM, Stephen wrote:
> On 6/8/2017 12:50 PM, Bald Eagle wrote:
>> larger gear:
>>
>
> Hmm! I make it 193 teeth, counting on my fingers.
> If there is a discrepancy it is about 240° clockwise from TDC.
>
>
Opps! I just read your first post.
I've worked out a method to count* them in blender. The angle between 
the teeth is 1.865°. Which surprisingly works out at 360/193 ;)

* Count is too strong a word. Read number from screen is more like it. :)

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Counting gear teeth with POV-Ray
Date: 9 Jun 2017 16:20:00
Message: <web.593aca76a250e006c437ac910@news.povray.org>
Further development and analysis.

Might make some more headway over the weekend, if I have enough free round
tuits.


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From: Stephen
Subject: Re: Counting gear teeth with POV-Ray
Date: 9 Jun 2017 16:45:51
Message: <593ad0bf$1@news.povray.org>
On 6/9/2017 5:19 PM, Bald Eagle wrote:
> Further development and analysis.
>
> Might make some more headway over the weekend, if I have enough free round
> tuits.
>

That reminds me. A couple of months ago I started to design a "Square 
Uptoit". Same family but more linear. ;)

I suspect that either the original photograph does not have a high 
enough resolution or the conversion you are using is not good enough. Or 
both. That is just looking at the images.

That aside it is an interesting project.

-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Counting gear teeth with POV-Ray
Date: 10 Jun 2017 07:06:01
Message: <593b9a59@news.povray.org>
On 9-6-2017 18:45, Stephen wrote:
> On 6/9/2017 5:19 PM, Bald Eagle wrote:
>> Further development and analysis.
>>
>> Might make some more headway over the weekend, if I have enough free
>> round
>> tuits.
>>
>
> That reminds me. A couple of months ago I started to design a "Square
> Uptoit". Same family but more linear. ;)
>
> I suspect that either the original photograph does not have a high
> enough resolution or the conversion you are using is not good enough. Or
> both. That is just looking at the images.

I was wondering if Inkscape's ability to draw paths from images could 
help here? Just a thought.

>
> That aside it is an interesting project.
>

Very.

-- 
Thomas


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From: Stephen
Subject: Re: Counting gear teeth with POV-Ray
Date: 10 Jun 2017 07:33:08
Message: <593ba0b4$1@news.povray.org>
On 6/10/2017 8:05 AM, Thomas de Groot wrote:
>
> I was wondering if Inkscape's ability to draw paths from images could
> help here? Just a thought.

A good thought. I've used it to convert a building's ground plan into a 
heightfield. (I must go back to that project soon.)

-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Counting gear teeth with POV-Ray
Date: 10 Jun 2017 11:01:51
Message: <593bd19f@news.povray.org>
On 10-6-2017 9:32, Stephen wrote:
> On 6/10/2017 8:05 AM, Thomas de Groot wrote:
>>
>> I was wondering if Inkscape's ability to draw paths from images could
>> help here? Just a thought.
>
> A good thought. I've used it to convert a building's ground plan into a
> heightfield. (I must go back to that project soon.)
>

Yes, that are the kind of things Inkscape does very well.

-- 
Thomas


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