Loft rails giving errors

[harry.arthur4]

Hello,

I am trying to loft the attached model using 4 rails, I can only get inventor to use 2 of the rails.

I really need to use all 4 rails to get the correct shape.

The two horizontal rails work however the vertical rails do not, I have trying smoothing them and redrawing them many times with no luck.

Thanks,

Harry 

[kacper.suchomski]

Hi

At first glance, it looks like the rails will create self-intersecting geometry. The rail endpoints seem to be mixed up.

Make sure everything is set up correctly.

Alternatively, include a sketch of your target geometry for us to reference.

[harry.arthur4]

Hi Kacper,

Thanks for the help.

This is the exhaust stub I'm modeling, I am making press tools to remanufacture these.

They are from a WW2 fighter a P40 Kittyhawk.

Cheers!

Harry  

[kacper.suchomski]

1. The rails in the graphic appear completely different from the curves in the detail. Maybe it's an optical illusion. Can you attach your file?
2. Remember that the rails must be perpendicular to the sketch. If this is not the case in reality, you should prepare a slightly longer model and then cut it accordingly. 

[piotrekdoro94]

I've managed to draw something fairly similar though I'm not sure if the diameter of your part remains constant. It should work either way with some adjustments.

Whith complex lofts it sometimes helps to split your sketchlines. Here for example you could try to divide your slot and circle into four quadrants so that the loft rails guide the geometry from line/arc endpoint to endpoint. You could also try  to loft each of the quadrants with only two rails as a surface, then close the openings and fill them in to create a solid body. Then just shell it.

[blandb]

Here is a quick sample part 2024. There is a centerline loft that is present in the model, but if you suppress it, the un-suppress the rail loft you will see a difference. The rails are perpendicular to the planes, and you can dimension the handle lengths of the splines to your needs. You could also dimension the radius of the splines that those locations as well, I just left them blank.

[johnsonshiue]

Hi! I would try creating two Lofts. The first one is from the exhaust (the big circle) to one of the inlets (smaller circles). The second one is from the exhaust to the other inlet. Then try fill the gap between the two Lofts. Lastly shell it to the desirable thickness.

Many thanks!