Boundary patch behaviour

[j.volkmar]

Hello,

i want to create a pocket on a surface, where the floor of that pocket is the same shape as the outside surface. I attached a file that shows the steps I'm taking, but the boundary patch that forms the floor of the pocket is some weird shape that does not follow the outside surface. 

The floor surface (marked in blue) should follow the shape of the outside surface

but instead its bowed inwards:

How can i achieve it so the boundary patch follows the shape of the outside surface ?

Thanks for any help.

Edit: Im using 2025.2 Build 293

[CGBenner]

@j.volkmar 

Hello, and welcome!  Thank you for sharing your file with the group.  It is always a good practice to mention the version of Inventor used to create the file so the experts here will know before they try to open it.  Can you share that with us?  Thanks, and good luck!

[CCarreiras · Accepted solution]

Hi!

I believe Loft Tool can create the surface you need:

Check the video:

[j.volkmar]

Thank you very much! I didn't even know the loft tool could do surfaces 😄 

[CCarreiras]

Almost every tool that is used to add solid can also do surfaces... you just have to select it 😉

[johnsonshiue]

Hi! For this case, I would not use Loft or Boundary Patch. I would use Offset instead. It is because neither Loft nor BP can honor the design intent of offsetting the original extruded surface. Please take a look at the attached part.

Many thanks!