Hi @snoofydog,
Thank you for sharing your picture.
If you would like to use the loft feature, you can follow this work flow here.
Option 1:
- Create a horizontal plane on top of your extruded spline with


2. Create a sketch on that plane and "Project" the edge to that plane
3. Create two more vertical planes and draw your profile, just make sure that the profiles are closed
4. Use the loft feature in the "Sculpt" environment to create your profile

5. once you have your profiles you can merge the edges and delete the faces you don't need manually
Here is the example file I have created for you http://a360.co/29HMbEN
Option 2:
From the shape I could see picture, I would guess you try to design a shoe?
Another option might just to design the entire shape in the "Schulpt" environment.
I have created a sample shoe like that below in approximately 10 min, so it is a great time saver and you have a lot flexibility.
Here is the link to the file. Please, feel free to use it. http://a360.co/29ssAnL

I hope this information helps.
Thanks,