What in the heck does G0, G1, and G2 mean?!!! And other LOFT problems...

[Anonymous]

Can someone please explain to me what G0, G1 and G2 mean? I swear I have *more* problems with failed loft creations over "not G1" and also "the rails do not intersect all profiles."

Can someone please explain what is going on? To be clear, I have confirmed *dozens* of times my rails do in fact intersect my profiles. I am talking about *days* worth of pulling my hair out over this. Please help... thank you!!!

(p.s., I am only 4 weeks into my Fusion 360 career, but I LOVE it.)

[TrippyLighting]

If you can share you're design that might save you some hair 😉

Export as .f3d and attach to the next post.

If I cannot help, I'll summon the loft experts. We've got a number of folks here on the forum that are very knowledgable in that area.

Here is an excellent explanation form the Autodesk Alias site.

@cekuhnen teaches that stuff at University Level and I find his explanations also excellent.

[Anonymous]

I've resisted sharing the design for a number of reasons, not the least of which is that explaining where to look (i.e., where the problem is), would probably take longer than simply zeroing in on the question itself. The file is one continuous work I now put about 100 hours into. The question is simply this: why do certain lofts fail, for the reasons offered by F360 ("rails don't intersect all profiles" reasons, despite the fact they do), and the G0, G1, G2 thing.

But also because I have about managed to make it work with alternative files whose only purpose was to prove the loft strategy to myself. I can get it to work sometimes, and other times it fails, and there doesn't appear to be a unifying reason that I can discern.

And judging by my search of similar threads, it doesn't seem to be publicly settled matter.

[cekuhnen]

@Anonymous

Check this : https://knowledge.autodesk.com/support/alias-products/getting-started/caas/CloudHelp/cloudhelp/2016/ENU/Alias-Tutorials-Legacy/files/GUID-E1BDFBD0-33CC-44C4-866D-5F367105A050-htm.html

also,I think that there are currently some issues with sketches that can result into the rail issue you mentioned 

[Anonymous]

I think I understand the problem.

If you create sketches or bodies that build on pre existing sketches and bodies, it is a frequent practice to have to use the project command to grab preexisting features (lines, edges, intersection points, etc), in order to have a starting place for the new thing you are working on.

If you do that, and you keep visible the preexisting sketch/line/point/wireframe/body, etc., then it is VERY easy to accidentally use one of the preexisting points (edges, intersections, etc.) as your snap to position, for things like loft profiles, rails and so on, when in fact you need to be snapping them to the immediate sketches you are working on.

You can zoom in forever, and it will be correct when judged by intersection and by appearance. But logically it will be the case you have snapped your (e.g., loft rail) to the wrong sketch. And there is no way, as far as I can tell, to visibly tell either way simply by analyzing your sketches.

The way you guarantee you haven't done that is to turn off the visibility of those other sketches/bodies when creating your new things (e.g. loft rails and profiles). The moment I realized this, I was rewarded with success.

I am not 100% sure this is the full answer, as I have experienced dozens and dozens of failed lofts over the past couple weeks, but I am going to move forward as if I have a new significant piece of understanding. I hope this helps someone.

P.s, Re reading what I wrote seems a bit aggressive in my tone and I apologize if I came across that way. I was frustrated, but that's no excuse.

[Anonymous]

Thank you very much for the link. I was searching forever about what the heck they meant, and came up short.

[davebYYPCU]

(Quote)

The way you guarantee you haven't done that is to turn off the visibility of those other sketches/bodies when creating your new things (e.g. loft rails and profiles). The moment I realized this, I was rewarded with success.

I am not 100% sure this is the full answer, as I have experienced dozens and dozens of failed lofts over the past couple weeks, but I am going to move forward as if I have a new significant piece of understanding.

(Quote)

Yep that is how I manage it, It is a work around but

that says it the way it works for me too.

I have also a testing method before going too far, I make all rails first, if I can, then first two prolifes and see if Loft will build the 1st section with all rails, if so, cancel Loft and contimue with profiles, testing each new one.  Helps identify where the rail/s isn't intersecting, before you have a huge deciphering job.

The other one that gets me is the rails tangent to profile error,

I think I have a system for that, works with splines, and I have almost committed to 100% splines for rails.

[cekuhnen]

@davebYYPCU

Yeah thats a common mistake I also see with my students! The loft cannot offer G1 G2 when you select a sketch edge.

You can hide the sketches or press and hold left mouse button on the sketch/body edge and a pop up will appear giving you

the ability to select the object below the mouse cursor you want.

@Anonymous 

No harm done - CAD can be frustrating when you are new to the system.

[GoodDogBadDawg]

Give it time

[GoodDogBadDawg]

give it time

[TheCADWhisperer]

@GoodDogBadDawg 

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