Lofting with guide rails

[User101010]

Hello, as a newbie to Autocad 2014/64 I try to get a pyramid like shape lofted from a rectangular structure as base. As long as I try this in demo mode (simply using a rectangle and a lifted circle and/or point) this works.

In my special case this works only as long as I use no guide rails. Upon entering the first guide the loft collapses with a useless error message.

I have verified those guides being splines really starting from the surface and the endpoint, respectively. I can'even loft along straight polylines 😞

What did I miss since 3 weeks of trials in vain? I do hope that this is well within the capabilities of Autocad. File corrupted?

Thanks in advance

Annette

[JDMather]

Did you leave layers on with extraneous information to add confusion to the basic problem description?

(For example - I don't have a clue what purpose Rumpf01_verdeckt layer has to do with the problem description.)

I had trouble understanding your design intent (or problem description), but is something like this what you are after?

[User101010]

Thank You for Your immediate care,

this file is a cut out from the drawing of a model aircraft fuselage, so the underlying 3view images are attached on the xref layer. Of course theree are many reference lines You can ignore (in pink)...

The loft should extend from the rectangular base plane (3 versions to choose from with sharp / rounded-off / cut-out corners) to the rear end marked by a circle for easier point snap. Guide rails should be the 2 red and 2 yellow splines - but even the 1-segment poylines don't work!

One related question: in the help file I found a table of loft options. Are these to be read line – wise or is any combination of cross section /path / guide rails possible?

Thanks again

Annette

[JDMather]

One problem at a time.

Post file with ONLY the geometry you intend to use for the first loft.

You did not make any comment about the file I posted.  How did it not meet your design requirement?

If you are a student I recommend that you download Autodesk Inventor (http://www.autodesk.com/edcommunity ) as it sounds like a more appropriate software for this design.

[JDMather]

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@User101010 wrote:
 Of course theree are many reference lines You can ignore (in pink)... 

Annette

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Then don't include them or hide the layer. 

[User101010]

According to Your suggestion I have stripped unnecessary layers with exception of the circle marking the top of the pyramid. The problem reduces to lofting from the yellow rectangle with rounded corners on layer “Rumpf01_verdeckt“ along the 2guide rails on the same layer and 2 other guides in red “Rumpf01” to the top. In despair, I even tried to use 2 straight polylines as guide rails – but without success.

Please understand that I cannot mark this response as "Accept as Solution" at this stage.

I have just become a bit familiar with Autocad which took me quite some time...

If You state it's a no- go I perhaps will have to work through Inventor too, although could not a priori imagine that I might need the cavalry for lofting...

Thank You for Your patience  

Annette

[JDMather]

1. The curves on Rumpf01_verdeckt do not meet at the apex (slight overlap).  This is the primary problem.

And they are not connected at the Querschnitted Rund loop.

2. There are extra lines in the Querschnitted Rund loop (these don't really matter, except not good modeling practice).

3. I do not understand the purpose of Rumpfenden in creating this Loft?

Extract the attached file and in your file run the ACISIN command.  Change the SHADEMODE.

[JDMather]

Did you figure out our Loft?
Are you using Osnaps?

You might look into using Constraints on the Parameters tab for extra insurance.

[User101010 · Accepted solution]

Sorry for the delay, thank You for the ACIS file. Friday I tried to open it: Unzipped, ACD response: file not found. Verified file properties etc: after 1 hour of try with re-downloading the file, importing it from various sources I decided that I need a break. This helped. Today I was successful to get Your near-perfect loft volume. I verified that in my original drawings there definitively was no connection between the cross-sections and the guide rails: typical dumb beginner's fault, but I would have sworn everything was perfect... Is there any command to verify true intersection? No, I did not use orthogonal snap as my design is only orthogonal in one plane. Could You please give me a link what You mean with “Constraints on the Parameters tab”? Next task will be to smoothe the 4 edges further making the star-shaped isolines more circular. For that reason I attach my NURBS extrusion from my old file, now corrected. Any hints would be appreciated. BTW, I conclude that the table of allowed lofting combinations in the loft help function don't need to be read row wise. Thank You once again Annette

[JDMather]

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@User101010 wrote:
.... Any hints would be appreciated. ...

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...

I would forget using AutoCAD for something like this since Inventor is so much easier to use for something like this.

BTW to open the *.sat file I posted you only needed to

1. Open your dwg file

2. type acisin command and follow the command line instructions.