BoardCAD How to add single concave and channels bottom?


I want to add single concave (also channels) by moving up the center control point of the cross section in BoardCAD. Who knows how to do that please? See the attached picture.

I know I can lower the rail control points at the sides - i dont wanna do that. It changes the rail rocker; its complicated, you need to re-check all the other crosssections…

Why cant we just move up this goddamn center point (at the bottom of the Cross section) to create a simple concave?  :-))))

I make hollow skin and frame wood surfboards, so no taking a surform and sandpaper and make the concave by hand…unfortunately

Maybe the guys behind BoardCAD (Haavard?) can answer this, please? The very small section in the BoardCAD Book (CTR, SHFT, drag the points) doesnt really address this issue of the center point being locked.

How do you guys make your concaves in BoardCAD? Some sort of 3D advanced NURBS editing i didnt get?



this is how i proceed usually:

design a board in BoardCAD -> open .brd file in jedails HBTM, create full template of spine and ribs  -> open .pdf in COREL DRAW, clean up everything like double lines, unclosed vectors etc… -> open .dxf in VECTRIC, create the toolpath and send to my CNC. 

until now i made the concaves in COREL DRAW by modifying each rib individually (simply adjust the vector curves) BUT:

-this doesnt give me the exact surfboard volume at the end.

-its more work.

It would be much simpler if the wooden surfboard guys could add complex bottom contours directly in BoardCAD. You get the volume right on, and work with clean files from the beginning.


Thank You very much for these awesome FREE softwares nevertheless ! Cheers, Gab 


Gab, click on the gray control point, in the middle of your red circle, once or twice until it turns blue, then you should be able to move it, the same way you did with the red one. -J

Dear J Randy,

Thank you very much for your quick answering! I really appreciate it! thank you for your screenshots also :slight_smile: Finally it worked. (but very strange: on the one crossection i was working on (a default one), it still didnt move. I added a new CR, it worked. I opened a new board (shortboard), it worked too!

maybe it was a bug…

if there is anything i can help you with in return , please let me know.

cheers, Gab

You are welcome Gab. I have learned so much here on Sways that it is good when I can offer something back.

Keep on trying, that is the best way to learn.

Hello @Gabriel Dos Santos,

I have the same problem too. I managed to move the blue center point up and down in “cross section” … and now impossible!

What’s the problem?


Houra!!!, I find the way!

Modify the doc with savind in .stp   (back up at each step with a new name for more security)

More clearly:

-save the doc in .stp

-save the .brd and close

-opend the .stp doc and modify the simple concave (change view, for seing the cross section).

-save the doc in .brd, it’s appears with the new concave, great!