Create a Ramp with Fillet Rectangular Shape

Hello All,

I am a Rhino beginner, and I am trying to create a ramp with a filleted rectangular shape. I try severval methods that commonly been used to create ramp, but all of them failed. The methods I tried include:

"CreateUvCurve": It failed because it does not allow me to do so with polysurface.

"ApplyCrv": It said that one curve was not in the world XY plane and was not applied to the surface.

"FlowAlongSurf": It keeps asking to select edge near matching corner; it is just not responding

"ProjectCrv": It said the projection missed the selected objects.

I feel like I am really running out of option, what can I do to?

Hello- please post a Rhino file and give some indication of what you would like the results to be.