HELP any idea on creating a solid from the sketch?

[Anonymous]

Hey all,

I draw two profiles 1st concave and 2nd rectangle on two planes.

Then I've connected the edges with 4 splines.

Tried creating loft using the profiles and 4 splines as rails and failed.

I undestood it fails because the rail can't be tangent to a profile.

Any ideas on how to create a solid out of those sketches that would have the same shape as the imagined loft?

[gautham_kattethota]

Hi,

I see some issues with the sketches that is resulting in the loft failure.  I will get back to you soon on this.

Gautham

[gautham_kattethota]

I see two issues with the sketches that was leading to the failure:

1. One part of the concave sketch has two curves that are overlapping.  See the attached image.

2. The two curves used as rails in "Left Rails" sketch have some issues.  They were not exactly touching/intersecting one or both profiles (they appear to be touching, but there might some small numerical noise).  I reconstructed them (hopefully) the exact way you had constructed.

After resolving these two issues, the loft works fine.  Please see the repaired file: Loft_repaired.f3d.

Let me know if you have any further questions.

Regards,

Gautham

[Anonymous]

Hi Gautham,

thanks for your quick reply and repairing.
I can't open the .f3d file because the file was saved with the newer version.
Seams I have the latest public version.

Meta Type: GeometryBase3DMetaType
Persisted Meta Type version: 2
Current Meta Type version: 1
Persisted Software version: 2.1.3029
Current Software version: 2.0.1761

Do you have any suggestion how to ensure the sketches intersect?

I figured out that the loft solid can also be created by editing and thickening plane in sculpt. Still not sure which approach is better. But it seams that in sculpt it's easier to tweak the design but than again the edit value is always absolute - it doesn't show the primary entered edit value if editing the same part again.

[gautham_kattethota · Accepted solution]

Sorry about that, the file I attached was from an internal build hence you couldnt open it.  I have now attached the file "Loft_repaired_profile_leftRail.f3d" that you should be able to open.  There are still some issues that I see using the sketches (which we will investigate), but when I use the two profiles and the 4 rails, I get a good loft.  

Whether to use Loft or Sculpt depends on your requirements for the design.  If it is an engineered part that you are trying to design, which requies precise values, it is usually best to stick with modeling features such as loft.  Sculpt is good for generating organic shapes, which as you have seen, is very easy to modify and get it to the desired shape.  But it is harder to maintain precise values and dimensions with sculpt.

Regards

Gautham

[gautham_kattethota]

I see another issue with the concave sketch.  Near the middle of the top curve, there is a very small line with two tangent constraints with its adjacent curves.  It appears taht this small line was added as a filler to join the two splines together.  See attached image to get an idea of where this small line is.  Such small curves can cause modeling issues downstream - for eg., by producing a very small face compared to the rest of the model or producing weird results.  

It is generally best to avoid such small curves, and also, as I pointed out before, overlapping curves.  A good way to avoid overlapping regions in sketch is to use Inferencing (which you get by default) - when  drawing sketch curves, you get close to an existing curve's end point or other work points, the cursor changes shape to tell you that it has detected something to 'lock' to.  When you use this inferencing, it implicitly adds sketch constraints to ensure that the curves remain well connected.

Hope this helps.

Gautham

[Anonymous]

Gautham,

no problem, thanks again. I carefully redraw the sketches and got the desired loft.