(HELP) Cannot get the loft command to work with rails

[Anonymous]

Hello,

I am new to inventor and am struggling with the loft command for quite some time now. I mostly get by with simply bypassing the loft function all together and using some other workaround but it seems the loft option is the only option in this case. I have created 2 cross-sections (sketches) and wish to use the loft command to create a profile between them. The following problem occurs:

1. I use the loft command and select the rails function.

2. As sections I select both sketched cross-sections and inventor previews a straight loft between them.

3. I want the lofted profile to revolve around a central point so I select a circle which contacts both sketches and has the required radius needed for the loft to follow.

4. An error occurs telling me the rail curve does not intersect with one or more of the selected sections.

See attached images for clarification. If need be I can provide the .IPT file upon request.

Any help would be greately appreciated. Thank you all in advance!

[andrewiv]

Please provide the ipt file and I can take a look at it.

[johnsonshiue]

Hi! The error message indicates that the smaller circle does not intersect one of the profiles. For guide rail loft, the rail has to intersect all the profiles on the boundary.

Please share the file here so forum experts can help take a look. 

Many thanks!

[Anonymous]

Thank you for your response! I have attached the IPT file to this message for you to look at.

[JDMather · Accepted solution]

You missed one of your corners.

(Don't forget that you Offset a plane.)

[JDMather]

But I would start to question how you are going to manufacture that?

I suspect that you should do Revolves rather than Loft.

[Anonymous]

Thank you so very much. I must confess I could not detect any missing intersections between rails and sections.

As far as manufacturing is concerned these will be 3D printed in ABS with a 0.5 micron resolution so no machining is required. How would one use the revolve command in this case to blend both sections? I lnow how to revolve a single section and that is about it.

[JDMather]

---

@Anonymous wrote:

 I must confess I could not detect any missing intersections between rails and sections.

Did you see it now,  after I pointed out the missing intersections and attached the file?

[Anonymous]

I see now yes. I foolishly used the wrong centerpoint and forget about the 0.2 mm offset making one of the cross-sections not align properly. I have modified my sketch and added an additional rail in the bottom middle of each section as you have done in your example. I also altered the dimensions of each section so they are slightly 'taller'. Each rail now has direct verifiable contact with both sections.

Nevertheless I am still not able to use the loft command. Instead of any error messages I am now simply unable to finish the lofting process with the 'OK' button being greyed out. Furthermore every time I select 'CLICK TO ADD' a new rail selection it seems to erase the previously selected rail, with only one sketch present in the column at any given time (see attached image).

Again, I greatly appreciate your help. I do apologize if my responses are somewhat untimely for you. 

[JDMather]

No file Attached?

You don't need those construction circles - I only left them in to illustrate the issue.

[Anonymous]

Oops, my mistake. See attachment.

[JDMather]

I am totally confused now.

I do not see any rail sketches in  your latest file (rails must be object linetype, not construction).

[Anonymous]

Aha, I did not know that. I made all my rails construction geometry as it made it easier for me to distinguish between sections and lines to follow. I am now able to complete a loft without a problem! Thank you very much for your assistance, and best of luck to you.