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Trying to Loft a hook

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JD Mather

Then I lofted the main center section using all of the rails.

main loft.png

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JD Mather

Then I blended the end to the middle section using Loft with G2 smooth tangency. Keep in mind to select the center rails you have to pick twice - once to select the sketch and a second time to select the rail.

Finally, I added Variable Radius Fillets to the hook edges. This takes a lot of experimentation and prior knowledge to get them to work out.

 

Now that you understand the geometry doing different itterations takes much less time.

Smooth transitions loft.png

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JD Mather

I should have pointed out - when doing blending fillets like shown in the previous post - select the faces of the part rather than sketches for the section profiles or you won't get the option for G2 tangency.

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lis_wang

How to create this hook in the attached file?

 

Would you like to email the hook you created to me?

hook.jpg

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JD Mather

Attach what you have completed so far.

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lis_wang

The attachment is the hook I created. I do not know how to make the sharp corner to sphere R6.

hook.zip

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lis_wang
The attachment is the hook I created. I do not know how to make the sharp corner to sphere R6.

 

I have amended the hook. Please take a look.

hook.zip

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JD Mather

This could be simplified a bit more as a couple of the sketches aren't really needed. The Workpoints aren't really needed. Well looks like I will have to simplify as it won't quite fit here because of filesize. Just realized I had the Spherical Radius as 2 rather than as 6 like print dimension. I will post corrected attachment when I get it under 250K.

Hook.png

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JD Mather

I made a mistake causing to have to do the Loft as a surface and then Sculpt to get solid (bit tricky to explain the mistake). So the Sculpt is an extra step, but you should get the idea.

To reduce file size I omitted the cylinder, chamfer and thread.

Hook_JD_Rev1.zip

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lis_wang
I made a mistake causing to have to do the Loft as a surface and then Sculpt to get solid (bit tricky to explain the mistake). So the Sculpt is an extra step, but you should get the idea.

To reduce file size I omitted the cylinder, chamfer and thread.

 

I have not problem to create loft for your "sculpt1" as solid output. But I cannot create the loft as your Loft 1. My problem is I cannot select the outer portion of sketch 1 (the arcs of R70 and R82) as Rails. How did you manage to select sketch 1 twice as rails?

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linnmaster
I have not problem to create loft for your "sculpt1" as solid output. But I cannot create the loft as your Loft 1. My problem is I cannot select the outer portion of sketch 1 (the arcs of R70 and R82) as Rails. How did you manage to select sketch 1 twice as rails?

 

HI ...

When you pick the the rails ... you have to select each rail twice. You'll see when you pick one rail, on the very bottom of the screen in the message bar, it says something along the lines "sketch contains more than one open loop, and you need to pick one".

So, when you select your first rail ... select the inside curve, it will only highlight partial ... place your cursor over the same rail again, and it will highlight the entire curve up to the radiused end.

Add new sketch, and do the same with the outside curve ...

 

Should work ...

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linnmaster

My question is why can't the first loft be created as solid? It seems to fail and only works with surface ...

 

And the other question is that for Loft1, you've got both tangent conditions on both edges that are selected ... When I tried tangent on both, it turns really ugly ... only on the edge at the tip radius 6 end it becomes more like "normal" when the "tangent" condition is selected ... the other end is fine and works with tangent, like it should. Any idea why the different results between the two?

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shift1313
My question is why can't the first loft be created as solid? It seems to fail and only works with surface ...

 

And the other question is that for Loft1, you've got both tangent conditions on both edges that are selected ... When I tried tangent on both, it turns really ugly ... only on the edge at the tip radius 6 end it becomes more like "normal" when the "tangent" condition is selected ... the other end is fine and works with tangent, like it should. Any idea why the different results between the two?

 

 

which hook are you speaking of? JD used Smooth(G2) tangency. It will produce a different result than tangent.

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JD Mather
My question is why can't the first loft be created as solid? It seems to fail and only works with surface ...

 

If you test the closed sketches in my previous model by trying to Extrude you will see a red cross in the dialog box. This is associated with coincident points that did not merge. (Tip: Doing Extrude even when my end design intent is not an extruded feature is the easy way that I test closed sketches for this problem.)

In Rev2 I have fixed things up.

 

 

When I tried tangent on both, it turns really ugly ... only on the edge at the tip

 

Attach your file here. In my file you should notice that the tip is only part of the spherical feature (not a hemi-sphere).

Hook_JD_Rev2.zip

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linnmaster

I can't seem to get my file small enough - I'm out by 8kb ... here is a screen shot of what happens on the final loft3 when both edge conditions are set with tangency condition ...

 

Anyways, I just recreated the features that JD did on his (or tried to), using his sketches ... and it seems like my end result is different ...

 

hookdl.jpg

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linnmaster

I just realised something ... I seem to have two solid bodies ... and I think this is creating my problems seen above ...

 

Nope ... got it as one solid, but symptoms are still the same as above with tangency condition set on both edges on final loft ...

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linnmaster
If you test the closed sketches in my previous model by trying to Extrude you will see a red cross in the dialog box. This is associated with coincident points that did not merge. (Tip: Doing Extrude even when my end design intent is not an extruded feature is the easy way that I test closed sketches for this problem.)

 

JD. Not sure quite what you mean as all your closed loop skteches do Extrude. However, there is a red cross in the dialogue box that shows up, but, it's for the sketch that contains the rails ... which is of course open.

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linnmaster
which hook are you speaking of? JD used Smooth(G2) tangency. It will produce a different result than tangent.

 

In JD's model, he didn't use Smooth(G2). He used Tangent. When I use Tangent, I get what you see in my screen shot above. To get something similar to JD's rev1 model, I had to use Free. Using Smooth(G2) becomes too fat.

 

Regards,

David

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JD Mather
JD. Not sure quite what you mean as all your closed loop skteches do Extrude. However, there is a red cross in the dialogue box that shows up, but, it's for the sketch that contains the rails ... which is of course open.

 

 

I didn't say they won't extrude (the closed profiles, not the rails sketch). I said in the original example I posted if I try to extrude as a test of the quality of the closed profile sketch there is a red cross (they will still extrude).

 

In the second example if you try to extrude (the closed profiles) as a test there is no red cross.

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JD Mather
...here is a screen shot of what happens on the final loft3

 

Did you take a look at the Rev2 file I posted? You need to be careful where you select the edges for the loft. Click on the planar faces near the edge or the tangency will be to incorrect face.

 

Note also that must have existing solid faces or surfaces to get the tangent options. Lofts with sketches do not give this option.

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