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Equations for 16:9 rectangle driven by diagonal dimension

Equations for 16:9 rectangle driven by diagonal dimension

Equations for 16:9 rectangle driven by diagonal dimension

(OP)
May be I'm being too quick on the trigger by posting this question here.

I'm trying to create a sketch of a rectangle that has a 16:9 ratio (yes, a widescreen, you guessed correctly).  I want to add equations to the width and height to maintain the 16:9 ratio, but I want to the size of the rectangle to be driven by a diagonal dimension.  Any suggestions?

RE: Equations for 16:9 rectangle driven by diagonal dimension

(OP)
One solution I just tried was dimensioning the diagonal "construction" line and the angle between that line and one of the sides (after creating a 16:9 ratio rectangle).  It seems to work, but I'd like a more "scientific" method using equations.

RE: Equations for 16:9 rectangle driven by diagonal dimension

You mean something like the Pythagorean theorem winky smile

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Equations for 16:9 rectangle driven by diagonal dimension

Attached is an Excel spreadsheet with the formulas already worked out for you.  Enter a 'Diagonal' and it will give you the Height and Width of a 16:9 (widescreen) rectangle.

Since I'm NOT a SolidWorks user you'll have to figure out how these formulas would be formatted in order to define your 'sketch'.

Have fun winky smile

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Equations for 16:9 rectangle driven by diagonal dimension

You're trying too hard. Just make a rectangle that is 16:9, draw a diagonal, and add an angular dimension from the diagonal to any side. This will maintain the 16:9 ratio and allow you to stretch and resize and control size with only one dimension (even diagonal).

batHonesty may be the best policy, but insanity is a better defense.bat
http://www.EsoxRepublic.com-SolidWorks API VB programming help

RE: Equations for 16:9 rectangle driven by diagonal dimension

Once you have it set up you can read off the horizontal and vertical dimensions from reference (driven) dimensions given the diagonal (driving) dimension.

RE: Equations for 16:9 rectangle driven by diagonal dimension

But cinnamongirl stated that she didn't WANT to use the constraint angle method, which she acknowledged was possible, but rather work it out using "...a more "scientific" method using equations."  Thus my spreadsheet example, complete with a "scientific" method winky smile

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Equations for 16:9 rectangle driven by diagonal dimension

(OP)
Well, my hope was that there would be an easy equation like X is the width, and Y (the height) is always 9/16 of X, even if X is not defined.

I suppose I could use the figures in JohnRBaker's spreadsheet to create equations between the sides' and the diagonal construction line's dimensions, but I think I'm going to stick with using the angle for now.  Thanks to everyone for your help.

RE: Equations for 16:9 rectangle driven by diagonal dimension

Well just remember, geometry is what it is...

I'll challenge anyone to come-up with a simpler 'equation-based' solution than what I proposed.  That being said, are you suggesting now that you're NOT interested in having the Diagonal distance as being the only variable?  After all (from your initial post)...

Quote (cinnamongirl):


I want to add equations to the width and height to maintain the 16:9 ratio, but I want to the size of the rectangle to be driven by a diagonal dimension.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Equations for 16:9 rectangle driven by diagonal dimension

Deliberately making a problem more complicated is not "scientific".

RE: Equations for 16:9 rectangle driven by diagonal dimension

Height = sin(arctan(9/16)) * diagonal

Apply appropriate SW syntax to the above equation. Pat yourself on the back for being more "scientific".

RE: Equations for 16:9 rectangle driven by diagonal dimension

(OP)
TheTick, thanks that equation worked (except I applied it to the width, not the height).

I hope we all learned something from this thread because I think I may end up using the angular dimension solution after all.  We paid so much for SolidWorks, might as well take advantage of its powerful tools.

RE: Equations for 16:9 rectangle driven by diagonal dimension

cinnamongirl,

   Draw the rectangle sides as line segments.  Do 16 on the bottom, and 9 on the sides.   

               JHG

RE: Equations for 16:9 rectangle driven by diagonal dimension

I love word problems! Is this plasma or lcd? Where are the speakers mounted? How large is the bezel? Table or wall mount?

Sorry, a little shaky from a late lunch. Diego

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