linnmaster Posted August 31, 2010 Share Posted August 31, 2010 Trying to create flat pattern so that the flat pattern is circular. I've had to remove most of the features to get the file size small enough for upload. What needs to happen is that the 2D sketch needs to be projected onto the curved surface to create a 3D sketch and "warp to surface". Surface then needs to be split to get a surface of just the donut. The donut needs to be thickened to 4mm on the side towards to axis. The flat pattern should be circular. But it's not. And I'm not quite sure why it's not. Thanks in advance for your help. Regards, David Copy of Part106.zip Quote Link to comment Share on other sites More sharing options...
Pablo Ferral Posted September 1, 2010 Share Posted September 1, 2010 I'm not sure that it should be circular. As soon as you wrap circle around a cone, the developed shape will no longer be a perfect circle. If you need a circular flat pattern, perhaps you could start with the doughnut and 'bend' it instead. http://inthemachine-autodesk.typepad.com/blog/2009/01/bend-what.html Quote Link to comment Share on other sites More sharing options...
JD Mather Posted September 1, 2010 Share Posted September 1, 2010 It worked fine for me, but there is something fishy with the file. It is way too slow and way too large of a file for this little amount of geometry. I will redo from scratch when I get a chance. Quote Link to comment Share on other sites More sharing options...
linnmaster Posted September 1, 2010 Author Share Posted September 1, 2010 Thanks for your help. I cannot bend in this case as it's a cone, which means that the bend radius is constantly changing along it's bend length. Quote Link to comment Share on other sites More sharing options...
linnmaster Posted September 1, 2010 Author Share Posted September 1, 2010 It worked fine for me, but there is something fishy with the file. It is way too slow and way too large of a file for this little amount of geometry. I will redo from scratch when I get a chance. I get the model working fine, but what you say with regards to a fishy file does seem possible. Is your flat pattern perfectly round? I confirmed that my development was not round by sketching a circle in the flat, and you'll find that the edge of the sketch circle and the developed circle cannot coinicide. It would appear that the developed donut shape is still elliptical. Quote Link to comment Share on other sites More sharing options...
Pablo Ferral Posted September 2, 2010 Share Posted September 2, 2010 Try making the cone a cylinder and checking the result. Now make the cone a really sharp cone and check the result. See what the discrepancy is. If it gets greater as the cone gets sharper, then you've proved that a circle wrapped round a cone and then developed is no longer a circle (at least to Inventor!). Quote Link to comment Share on other sites More sharing options...
linnmaster Posted September 3, 2010 Author Share Posted September 3, 2010 Try making the cone a cylinder and checking the result. Now make the cone a really sharp cone and check the result. See what the discrepancy is. If it gets greater as the cone gets sharper, then you've proved that a circle wrapped round a cone and then developed is no longer a circle (at least to Inventor!). Have done the same thing with cylinder. Actually, JD helped me with the solution in that case before, which I thought was a circular development, but checking it again, it's still an ellipse. Like in this case with the cone ... Quote Link to comment Share on other sites More sharing options...
linnmaster Posted September 9, 2010 Author Share Posted September 9, 2010 Any light on this topic yet? Thanks in advance. Regards, David Quote Link to comment Share on other sites More sharing options...
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