Loft+ rails issue.

[Anonymous]

Hi, guys!

I have a problem with loft and rail.
When I try to create loft with rail, I receive the following message.

I found solution here

https://knowledge.autodesk.com/support/inventor-products/troubleshooting/caas/sfdcarticles/sfdcartic...

But I can't set constrain,

It just doesn't work

Thank you!

[Logos_Atum]

Hello there,

as far as I can tell, Inventor has to guess how to loft the

sketches. 4 to 6 unsing midpoints?  Can you sketch what

you want to achieve?

Is the rail assigned along a wrong axis? Is the closed sketch

done in a wrong manner?

That´s not how it works...

Kind regards

Daniel

[hossaiy]

Hi S.Shivaprem,

The loft fails because the supplied rail curves aren't smooth, as you already saw in the error message. The issue appears to be at the end where the 2 rail curves join to the hexagonal profile. When you projected the edge of the hexagonal profile (for use in sketch 5 to join the rail cruve to it), because the edge isn't perpendicular to the sketch plane you get a line projected, as opposed to a point. So when you joined the spline to the end of the projected line the transition from the end of the spline to the projected line is non-smooth, thus the rail curve (combination of spline + projected line) is non-smooth.

It's a bit difficult to explain just with words, so i have attached a video here to show the problem and how to work around it (need to do the same on the other side with the other rail curve)

Hope it helps,

Thanks

[SBix26]

I believe all of this mess would have been avoided by properly constraining your sketches!  Sketch1, the hexagonal profile, is slightly out of alignment with the origin axes; Sketch2, the rectangle, is not centered on the hexagon; neither of them are dimensioned.  This is really poor modeling practice and leads to exactly what you've experienced.  Even if you don't know the dimensions that you want to end up with, get it dimensioned and constrained so that you can change it in a controlled way as you learn more about your design.

Sam B

Inventor Professional 2016 R3 SP1 Update 1
Vault Basic 2016 SP1
Windows 7 Enterprise 64-bit, SP1

[Anonymous]

Thank you, guys!

[JDMather]

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@Anonymous wrote:

Thank you, guys!

---

Post your new, corrected solution here.

[Anonymous]

I don't have it yet :))

I will post it tomorrow

Thanks for care

:))

[JDMather]

Before you start over - see time 2:05-2:07 in second video in this thread

http://forums.autodesk.com/t5/inventor-general-discussion/skillsusa-document-now-on-screencast/m-p/5...

As a beginner, you simply must follow the recommendations in this video (especially about the Origin Center Point).

I could make your file work (with the twisted profile) with a couple of extra WorkPoints, but I don't think that was your design intent. 

[JDMather]

Turn on your sound.

This video is very similar to the one 

@hossaiy  posted with audio narration.

[Anonymous]

@JDMather!

Thanks for the screencast and patience !

Here are two files with my loft experiments.

The first one is the hexagon. (loft + rails)

The second is "The free art" (loft-stam)

I have questions regarding the second file

1) Is there more simple way for getting the same result

2) Is there way for constraining splines? In this figure there are hundreds of dimesnions to be set

3)Is there way to constrain sketch15 without lock constrain?

[JDMather]

I recommend that you concentrate on simple geometry for the next few months, you need many more months of experience before you move on to complex geometry.

Post examples of simple models you have done.

(In the loft + rails.ipt file you have two sketch points that I did not show in my video - and they are not constrained.)

In addition to learning basic constraining techniques - you will want to become familiar with the difference between Sketch Points and Work Points.  These sketch points could be used rather than work points - but like everything a beginner does - they should be fully constrained.

[Anonymous]

@JDMather!

Thanks for your help!
I do appreciate that!

[JDMather]

Do you have a picture or link to something similar to what you are trying to model?

The first Loft feature does not look like anything I have ever seen in the real world - it looks "ugly" to me.

I suspect there is a better technique to get the geometry.

The best technique usually results in aesthetically pleasing geometry - and is often the simplest solution.

[Anonymous]

Thanks for reply!

I didn't try to model something special.

I just exeprimented with rail features in loft command

[JDMather]

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@Anonymous wrote:

I just exeprimented with rail features in loft command

---

Try this tutorial.

You will get error on image files - but simply select Skip All.

[Anonymous]

WOWWWWWWWWWWW!!!!!!!!!!

This is great!
This is what I need!

[Anonymous]

@JDMather, thanks for tutorial!

I don't understand what is need to be selected at pag 9-10.

Thanks!

[JDMather]

If a picture is worth a thousand words - a video might be worth a thousand pictures.

Attach your *.ipt file here and I will create a video when I get a chance.

[Anonymous]

Thanks!

I attached the file.

@JDMather,

It would be great to have video which includes the entier process

without skipping steps!

Thanks!

[mojtaba77f]

How can I make video like you?