Loft error on weight change

[Anonymous]

I'm trying to loft between these two faces and get this error. It will loft with the default setting under conditions but when I change it to tangent transtion and any weight value I get this error. I will try to post to CF. Any thoughts? I tried to create rails with a tangent spline but it wanted to include the lines in the sketch that the spline was created tangent to. No option to make them(the lines) construction geometry in a 3d sketch?

[Anonymous]

Kevin Vallelunga wrote... "I'm trying to loft between these two faces and get this error. It will loft with the default setting under conditions but when I change it to tangent transtion and any weight value I get this error. I will try to post to CF. Any thoughts? I tried to create rails with a tangent spline but it wanted to include the lines in the sketch that the spline was created tangent to. No option to make them(the lines) construction geometry in a 3d sketch?" >>>>>>>>>>>>>>>>>>>> One problem is point mapping related. Inventor uses a piece to piece mapping algorithm; e.g. edge_1a is matched to edge_2a, etc. A more sophisticated software will offer options that may yield an acceptable auto solution, but you will have to create the map points manually. (See attached.) Another (possible) problem: It appears (can't see the details in the pic very well) you are working with solid bodies and trying to create quilts. If you pick an internal quilt (or "solid") edge as a U wire (section)and specify a tangent condition how does inventor know which surface / face is the seed? Since you can't tell it (assuming this is still true in v8) I guess it's a 50/50 deal. If these are imported parts there will probably be other, more subtle, undetectable factors negatively influencing the outcome. If I were doing something like this in inventor I believe I'd.... (1) Delete the sheet capping faces. (2) Loft the transitions between the major faces. (3) Go back and fill in the gaps. (4) Stitch it all together. Alternative if you are trying to create a single solid..... (1) Pick the sheet capping faces for use as sections. I believe that inventor should properly identify the adjacent faces for tangency seed faces. (2) Define all your mapping points and loft as a solid. (I'd try this first with simpler shapes, but I think the chances of success with your shapes is iffy. Actually, my usual approach would be to delete all but a set of control faces for each body, create the transition, stitch and thicken. I don't think you want to attempt this in inventor, though.) Anyway you go about it you'll have to settle for G0 edge continuity in the V direction, which you may or may not see as a problem. Re using multi-segment curves for rails: After clicking on the sketch, click the desired segment a second time to select. Not sure this is necessary, though. Although rails must intersect the section curves I don't think they must terminate on a section curve (not sure and too lazy to test). At any rate, I don't see a need for rails for what you are doing, though could be missing something. =========================================

[Anonymous]

Kevin, I was able to have a weight as high as 0.5, but IV chokes on weights greater than 0.625. The resulting loft looks somewhat decent, even with the visualization (zebra stripe) tool. I agree with Jeff Howard that this is a rather complex loft to create automatically. As Jeff suggested, you might consider creating smaller lofts instead of all the geometry in one fell swoop (swoop that is, not Sweep), possibly using tangent rails as well. Also notice that if you un-check automatic point mapping, you'll see that some mapping points actually cross each other. I don't think this is desireable. You might also try manually dragging the problematic mapping points so that they do not cross each other. I've posted the model with the 0.5 weight loft to the CF discussion forum. I'm not sure how I got a non-zero weight to go in when you said non-zero weights are a no-go. I did uncheck automatic mapping, deleted all the mapped points, then added the condition weight of 0.5. I wish I could be more help, but at this point I think that if you want the loft to be tangent (G1), it is going to take some work. I think that even the high-end CAD modelers (Pro-E, Catia, Unigraphics) would have a difficult time automatically mapping the sections correctly. Best Regards, -Hugh Henderson (Autodesk) "Kevin Vallelunga" wrote in message news:40858a67_3@newsprd01... I'm trying to loft between these two faces and get this error. It will loft with the default setting under conditions but when I change it to tangent transtion and any weight value I get this error. I will try to post to CF. Any thoughts? I tried to create rails with a tangent spline but it wanted to include the lines in the sketch that the spline was created tangent to. No option to make them(the lines) construction geometry in a 3d sketch?