# Creating drawings from a photo.

• posted on November 8, 2003, 7:45 pm
Anyone have a site or instructions on how to create drawings from a photograph? I want to build a chair from a photo, but I'm having problems making the patterns first. I know the overall height, seat height, seat width/depth, but I'm trying to determine the splay of the legs, angle of the back spindles, curvature of the back rest. This is a Shaker Enfield dining chair (that I asked about several days ago with no responses).
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on November 8, 2003, 8:33 pm
The technique is called Descriptive Geometry. It's been a looong time, but the general idea is to start with a 3D drawing of a widgit (I have never done it, but I suppose a photo would work also). Draw in the lines of projection for the front, side, and plan views (back, bottom, and any other view of interest can also be used). Next, draw in reference lines perpendicular to the projection lines. With a pair of dividers, measure distances from the reference to points of interest on that particular face of the widgit. Transfer these points to your new drawing, the distance marked along the same projection line from the new reference.
Sorry about the garbled explanation. I used to have a book on it but it's either long since lost or simply has not been unpacked yet. I DAGS and came up with a bunch of hits, including a book that Amazon sells that appears to talk about theory, technique, and its application to CAD.
Good luck.     mahalo,     jo4hn
Phisherman wrote:

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on November 8, 2003, 9:04 pm
Thanks! I Googled "Descriptive Geometry" and there's a lot of reading for me to do. Very interesting and useful technique.

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on November 9, 2003, 4:23 am
Part of my software on my PC includes Visio. I've actually taken photos and pasted them into Visio, then drew lines on top of the photo. Visio calculates dimensions and angles for you. Its a no brainer, if you have photos that are fairly accurate. I've also taken photos that I knew were wrong (taken from an incorrect angle, causing perspective distortion) and put them in a graphics program to stretch 'em into relatively correct dimensions, then put 'em in Visio for size measurements.
Bob

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on November 9, 2003, 1:14 pm
Thanks Bob. I guess I could use Photoshop as I have this already installed. I may just try to do this without the computer and use obsolete drafting tools. Sometimes software is just too complicated (and I have a BS in computer science!)
On Sun, 09 Nov 2003 04:23:45 GMT, "Bob Davis"