Good morning All,

I'm trying to develop a simple flat pattern in SW for use as a template that the shop guys can use to lay on & trace a cutout contour on a large pipe where a smaller pipe intersects into it.  I've done these many times over the years, but always by trigging and/or using a DOS-based program (which I no longer use) to get my template.  I'd like to now be able to do these in SW if I can get accurate results (since it would be quicker and my DOS program won't work with Win7 unless i use DOS box to run it).

Basically, I have a simple layout of a 10sch40 pipe (10.75 o.d. x .365 wall) coming into a larger 24 o.d. by .5 wall.  The larger pipe will need a cutout in it to accommodate the smaller 10.75 pipe to slip thru it.  I need a template developed that would lay on the outside of the 24 pipe along with its centerlines (will be an ellipse).  I've modeled it and have attached it but its not complete (have 2 configs - first is called "no extrude cut" where I just have the pipe extruded outward with no cuts; second is called "extrude cut" where I don't have the branch pipe extruded outward but used the sketch to create an extrude cut which now leaves me 2 bodies but the inside cutout piece cannot be flattened to make the template but i can still flatten tube itself just not the smaller piece - last screenshot).  I made the larger pipe into sheet metal so that it can be flattened.  I made a 10.75 circle on the right plane and extruded it thru pipe.  I can make a 3dsketch of the cutout using "intersection curve" but couldn't get it to cut thru and then allow 24 o.d. pipe to be flattened for some reason.  I tried just extrude cutting the right plane circle sketch thru the larger 24 pipe and this worked but I'm thinking i'm going about this wrong?  Any ideas are appreciated in the best way to go about the method to develop one of these! Thanks in advance.

I did it the old school way just to get template out to shop.  It should be an ellipse 10.75" high x ~11-1/8" wide which wraps around pipe.