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Polar/Linear constant

26 REPLIES 26
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Message 1 of 27
Anonymous
207 Views, 26 Replies

Polar/Linear constant

Maybe some of you guys that weren't drawing cars or passing notes to girls
in math class could help me out on this one.

Say you make a circular pattern on an arc. In the parameters dialog you make
parameters for "RowCount" and "RowWidth". You want the RowWidth(s) to be say
1". RowWidth*RowCount gives you the correct width for the rows if they were
linear but what you actually want is the length of arc to be 1". Seems to me
like formula would be (RowWidth*RowCount)*some constant. Any idea what that
constant might be or what the formula would be to achieve this feat. Thanks
a bunch!
~Larry
26 REPLIES 26
Message 21 of 27
Anonymous
in reply to: Anonymous

The simplest answer, but maybe not what you want, is to use "Spacing" instead
of "Curve Length" in the pattern definition. This will, aside from not
covering the span of the part" measure along the curve and not straight line
hole to hole (what I call "pitch" and what Sketch2 is measuring).

If you want the pattern to cover the span of the arc (defined by "ArcLength")
with a specific pitch and count you will have to vary the arc radius. To
maintain the arc radius you will have to vary the span of the arc. Correct?
Not clear which you want to do.

Something else that might be adding to confusion is ArcLength being a linear
dimension (the subtended chord of the arc) while the pattern curve length
measures "on contour".

One thing you might do is layout an isosceles triangle with two legs
representing the BC radius and the third leg representing the pitch. A ref
dim from that could be used to drive a polar pattern or the legs of the
triangle patterned to use in a part outline definition.

I see a few ways to go, but don't know which will suite your purposes. Put
one in ivCF that maintains arc and varies span. The shape is driven by the
parameters "spaces", "count" and the radius in Sketch1.

==============================



"Larry Caldwell" wrote in message
news:00A04D66FA331EA6E1A5255AE0E809A5@in.WebX.maYIadrTaRb...
> Okay ... sorry for being unclear. I want to maintain the 1" hole pitch (or
> whatever pitch I need to make it 2" - 3"- whatever any value). That's what I
> was trying to relay about the constant/whatever, the 1" hole pitch needs to
> remain constant as the number of instances increases/decreases. If I set the
> center distance of the holes to 3" in the param dialog that needs to be
> maintained as in the driven sketch (hole pitch) regardless of how many holes
> I have. Everything else as you probably noticed changes size with those two
> user params so what I basically need is the hole pitch to stay at whatever
> value I put in the RowWidth parameter. Had to leave for a few minutes or I
> would have gotten right back to you. Thanks Jeff!
> ~Larry
>
> "Jeff Howard" wrote in message
> news:EFC4C2A8612483DCD162B8B69792B004@in.WebX.maYIadrTaRb...
> > Oops, no I don't see. If you can't get it sorted out can you relate a
> little
> > more of what your intention is?
> >
> > ======================
> >
> > "Jeff Howard" wrote in message
> > news:70F50972A7A65E1E41E1D6EA06DB5950@in.WebX.maYIadrTaRb...
> > > Never mind. I see that the part size is controlled by the pattern also?
> > >
> > > Still unclear whether you want the 1" on pitch or on arc len.
> > >
> > > =================
> >
> >
> >
>
>
Message 22 of 27
Anonymous
in reply to: Anonymous

Duh... driven by "pitch" and "spaces".

=====================

"Jeff Howard" wrote in message
news:BB2F3DBA43192884C3435E34BCEB0208@in.WebX.maYIadrTaRb...
>......
> The shape is driven by the
> parameters "spaces", "count" and the radius in Sketch1.
>
> ==============================
Message 23 of 27
Anonymous
in reply to: Anonymous

Larry, unconfuse me
I think we've got a classic circular reasoning problem here.
Are you really trying to work toward a radial distance solution, or
are you more interested in chord lengths? ie, linear offsets. Does it
need to solve for even and odd hole counts? The 5" dim that you called
arclength will preclude a radial solution, but will allow for a linear
offsets solution. Either way, I think polar pattern is involved. I
guess intent is always the 64k question.
"rowcount" vs "angle of throw" or "distance of throw"? With a 1"
pitch length as the final solve.
darvin

"Larry Caldwell" wrote in message
news:1F46BB0F0392DB1122B81062CB569190@in.WebX.maYIadrTaRb...
> Actually I started out with a sketch pattern but that's where I first
ran
> into the problem of trying to get the linear distance I want in the
params
> to actually be the length of arc for the hole pitch.
> ~Larry
>
> "darvinv" wrote in message
> news:506E33629AEEEFCD708F8308B8DFC477@in.WebX.maYIadrTaRb...
> > Yeh, and the mirror suggestion doesn't do even numbers. There's a
way,
> > but I'm not sure yet. Just a glimmer of an idea. You may have to
base it
> > on a sketch pattern, instead of a feature pattern nad use some trig
to
> > drive the sketch. Then, I think? that way you can accommodate even
and
> > odd numbers.
> > darvin
> >
Message 24 of 27
Anonymous
in reply to: Anonymous

Very good Jeff ... must be nice to be able to look down at those problems as
opposed to having to look up at 'em like I do. Thanks Ace! Think I can get
there from here.
~Larry

"Jeff Howard" wrote in message
news:C693429C7667C3809546727DB9639EB0@in.WebX.maYIadrTaRb...
> Duh... driven by "pitch" and "spaces".
>
> =====================
>
> "Jeff Howard" wrote in message
> news:BB2F3DBA43192884C3435E34BCEB0208@in.WebX.maYIadrTaRb...
> >......
> > The shape is driven by the
> > parameters "spaces", "count" and the radius in Sketch1.
> >
> > ==============================
>
>
>
Message 25 of 27
Anonymous
in reply to: Anonymous

Good thinking Darv! The (cordal length / count) should be the pitch of the
hole pattern and the calculated chordal length should equal what I've been
calling RowWidth or pitch. Having brought that up, it might be that the
formula for chordal length could be plugged into my parameters to get what I
have in mind. Now the question becomes: how come I didn't think of that
before. Thanks Darv now I have a lot of ways to go it would seem.
~Larry

"darvinv" wrote in message
news:6215E67C3625B8C0FFB0793655941FC8@in.WebX.maYIadrTaRb...
> Larry, unconfuse me
> I think we've got a classic circular reasoning problem here.
> Are you really trying to work toward a radial distance solution, or
> are you more interested in chord lengths? ie, linear offsets. Does it
> need to solve for even and odd hole counts? The 5" dim that you called
> arclength will preclude a radial solution, but will allow for a linear
> offsets solution. Either way, I think polar pattern is involved. I
> guess intent is always the 64k question.
> "rowcount" vs "angle of throw" or "distance of throw"? With a 1"
> pitch length as the final solve.
> darvin
>
> "Larry Caldwell" wrote in message
> news:1F46BB0F0392DB1122B81062CB569190@in.WebX.maYIadrTaRb...
> > Actually I started out with a sketch pattern but that's where I first
> ran
> > into the problem of trying to get the linear distance I want in the
> params
> > to actually be the length of arc for the hole pitch.
> > ~Larry
> >
> > "darvinv" wrote in message
> > news:506E33629AEEEFCD708F8308B8DFC477@in.WebX.maYIadrTaRb...
> > > Yeh, and the mirror suggestion doesn't do even numbers. There's a
> way,
> > > but I'm not sure yet. Just a glimmer of an idea. You may have to
> base it
> > > on a sketch pattern, instead of a feature pattern nad use some trig
> to
> > > drive the sketch. Then, I think? that way you can accommodate even
> and
> > > odd numbers.
> > > darvin
> > >
>
>
Message 26 of 27
Anonymous
in reply to: Anonymous

Ah shucks ... on second thought don't think that chord formula will work by
dividing it because while we would be talking about chord lengths, don't
think they would divide correctly because the total chord length at it's
angle wouldn't be the same as the individual chords at their angles. Oh
forgot ... yes I need even and odd hole counts. What do you mean by linear
offset solution?
~Larry

"Larry Caldwell" wrote in message
news:C1C0D755131E67B77351355EF2CB65B6@in.WebX.maYIadrTaRb...
> Good thinking Darv! The (cordal length / count) should be the pitch of the
> hole pattern and the calculated chordal length should equal what I've been
> calling RowWidth or pitch. Having brought that up, it might be that the
> formula for chordal length could be plugged into my parameters to get what
I
> have in mind. Now the question becomes: how come I didn't think of that
> before. Thanks Darv now I have a lot of ways to go it would seem.
> ~Larry
>
> "darvinv" wrote in message
> news:6215E67C3625B8C0FFB0793655941FC8@in.WebX.maYIadrTaRb...
> > Larry, unconfuse me
> > I think we've got a classic circular reasoning problem here.
> > Are you really trying to work toward a radial distance solution, or
> > are you more interested in chord lengths? ie, linear offsets. Does it
> > need to solve for even and odd hole counts? The 5" dim that you called
> > arclength will preclude a radial solution, but will allow for a linear
> > offsets solution. Either way, I think polar pattern is involved. I
> > guess intent is always the 64k question.
> > "rowcount" vs "angle of throw" or "distance of throw"? With a 1"
> > pitch length as the final solve.
> > darvin
> >
> > "Larry Caldwell" wrote in message
> > news:1F46BB0F0392DB1122B81062CB569190@in.WebX.maYIadrTaRb...
> > > Actually I started out with a sketch pattern but that's where I first
> > ran
> > > into the problem of trying to get the linear distance I want in the
> > params
> > > to actually be the length of arc for the hole pitch.
> > > ~Larry
> > >
> > > "darvinv" wrote in message
> > > news:506E33629AEEEFCD708F8308B8DFC477@in.WebX.maYIadrTaRb...
> > > > Yeh, and the mirror suggestion doesn't do even numbers. There's a
> > way,
> > > > but I'm not sure yet. Just a glimmer of an idea. You may have to
> > base it
> > > > on a sketch pattern, instead of a feature pattern nad use some trig
> > to
> > > > drive the sketch. Then, I think? that way you can accommodate even
> > and
> > > > odd numbers.
> > > > darvin
> > > >
> >
> >
>
>
Message 27 of 27
Anonymous
in reply to: Anonymous

The solve that jeff posted is basically linear offsets. Chord vs arc.
Distance of throw vs length of throw. They can drive either way. My
first assumption was that you wanted the arc length to the driver. You
could still do that, in Jeff's example, by using the arc length to find
the chord length.
darvin

"Larry Caldwell" wrote in message
news:57F867347D224D3C33337FD26AC3E2A8@in.WebX.maYIadrTaRb...
> Ah shucks ... on second thought don't think that chord formula will
work by
> dividing it because while we would be talking about chord lengths,
don't
> think they would divide correctly because the total chord length at
it's
> angle wouldn't be the same as the individual chords at their angles.
Oh
> forgot ... yes I need even and odd hole counts. What do you mean by
linear
> offset solution?
> ~Larry
>
> "Larry Caldwell" wrote in message
> news:C1C0D755131E67B77351355EF2CB65B6@in.WebX.maYIadrTaRb...
> > Good thinking Darv! The (cordal length / count) should be the pitch
of the
> > hole pattern and the calculated chordal length should equal what
I've been
> > calling RowWidth or pitch. Having brought that up, it might be that
the
> > formula for chordal length could be plugged into my parameters to
get what
> I
> > have in mind. Now the question becomes: how come I didn't think of
that
> > before. Thanks Darv now I have a lot of ways to go it would seem.
> > ~Larry
> >
> > "darvinv" wrote in message
> > news:6215E67C3625B8C0FFB0793655941FC8@in.WebX.maYIadrTaRb...
> > > Larry, unconfuse me
> > > I think we've got a classic circular reasoning problem here.
> > > Are you really trying to work toward a radial distance
solution, or
> > > are you more interested in chord lengths? ie, linear offsets. Does
it
> > > need to solve for even and odd hole counts? The 5" dim that you
called
> > > arclength will preclude a radial solution, but will allow for a
linear
> > > offsets solution. Either way, I think polar pattern is involved.
I
> > > guess intent is always the 64k question.
> > > "rowcount" vs "angle of throw" or "distance of throw"? With a
1"
> > > pitch length as the final solve.
> > > darvin

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