Make non coplanar surface


I am trying to make a surface that slopes in two directions. Like a driveway that slopes up and across. I can drawing the edges but I cannot create the face.
So its a polygon that is non coplanar that I want to create the face for.
How to do?


Make triangles (connenting endpoints with the ‘Line’ tool) of your geometry to obtain multiple faces.
Now smooth all inner edges to visually merge all these faces into one smooth surface.
You can use the ‘Eraser’ tool for that while holding down [Ctrl].


From this, I guess you want to create a surface that is tilted in two directions. In your example of a drive, it might be rising at a regular incline from one end to the other and in order to drain water to the side, it also has a slope across its width. Is that right? I ask because you go on to say

What I describe is not a polygon necessarily (could be a rectangle) but it is coplanar.

Can you home in further on what you are trying to do? Another example might help, if not an actual image.


One way to achieve a face that is tilted in multiple dimensions is to draw it aligned with the axis initially, then use the Move tool to rotate it multiple times. For example, first tilt it a few degrees “sideways” (to drain water) and then tilt it “down” (to meet the street). The rotations used to accomplish the tilts would be aligned with the world axes, rather than with edges of the object (which diverge from world alignment as progressive rotations are applied).


When you have drawn the edges, you can try using the Sandbox from Contours tool to put a surface between them.


Hi All…thanks for the help.

Yes if it slopes in just two direction it would be coplanar, that is the driveway slopes up and angles across. But what I an try to do is non coplanar …it slopes up and across, but the slope across is no uniform.

is there an demo example…YouTube??? I can’t seem to find.


SandBox Contour did the trick…thanks


It might help if you get to grips with the fact that all non planar geometry is made up of triangles. Sandbox tools simple build the triangles for you but understanding the underlying geometry is important.
Here you see as I scale the second side that SU uses ‘autofold’ to split the face into two triangles. If I delete the diagonal the faces are gone, but if I soften or smooth the edge (ctrl + Eraser) it appears to form a slope. You may not want it to slope this way so you can change the diagonal. More slope more facets and tris.