Unable to create solid or loft surface

You should be able to use Loft By Sections option. 

1. In the Loft Surface settings enable Force Start Point at Selection Point, Close Loft and Segmented Loft 
2. Select the b-spline profiles (hold ctrl key to select more than two profiles)  Note that the order of selection is important
3. To preview the lofted surfaces, data point to accept the profiles.
4. The direction arrows on the profiles should all point the same direction. If not Click on an arrow to change it's direction.
5. For a more consistent rule lines enable Rebuild Profile Curves and set the tolerance to .05 (the default setting of .01 doesn't seem to work) 
6. Data point to a create a Smart Surface. 

From the Solids tools use Convert to Solid to convert it to a Smart Solid.

I hope this helps.

Regards,
Ron

Hi Ron,
Thank you for your reply. I stitched all the surfaces together but when I want to convert to solid and point it at the surface there is a "No Entry sign" saying "Element not valid for tool smart solid/B spline curve" . DO you know what is wrong ?

I'm not sure why that isn't working for you.

Here's a video screen capture showing the method I explained in my previous post.

I'm not sure why that isn't working for you.

Here's a video screen capture showing the method I explained in my previous post.

Ron, Many thanks for showing me how you did it. After many tries I finally I get it. challenging for a beginner. The sequence of picking the lines matters.

Just some questions .Why did you use reverse direction on the last profile and then you reversed the third one ? Which mouse key did you use to preview ? Left click or right click ? What is the effect of rebuild profile with a tolerance ?
Thanks again.
Law Sp

Seems like Rebuild profile curves with a minimum of 0.05 is required. Does that mean 5% . that means 5% deviation ?

I only reversed the direction on the profile to show how it is done, and to show how it effects the preview.

To see the preview you just left click to accept the selected profiles.

By rebuilding the profiles the resulting wireframe has evenly spaced rule lines. This tends to improve the resulting surfaces.

I am not sure about the basis of the rebuild tolerance. I just made trial and error changes to it until I achieved satisfactory results. The value 0.05 maintained the shape of the profiles while producing evenly spaced rule lines. If you use too large of a number the profiles become distorted.

Ron,
I really appreciate your help. I tried your techniques on another more complicated part. I successfully created the surface but I am stuck with
"Unable to convert to Solid" when I try to convert to solid. I used smart solid. I could select the surface but gets this error.
The file is at.
www.dropbox.com/.../CANNOT%20_CONVERT_2_SOLID.dgn

If you can look at it I would really appreciate it. I am not sure where I go wrong.

SP

It didn't work for me either.

As a workaround I was able to make 3 simpler surfaces by only lofting 3 profiles at a time. These surfaces each converted to smart solids with no problem. Once they are converted to smart solids you can combine them into 1 smart solid with the Unite Solids tool (Keyin: Construct Union )