How can I change the width of some, but not all, steps in a stair run?

[Claire_AlgarinEVZUB]

I'd like to make the bottom steps in a run wider than the steps above.

I keep  getting "Invalid sketch, can't create run by this sketch."

Staircases with wider bottom steps are common so there must be a way!

(I'm aware the sketch shown can't work, the green lines are just to show the shape I want)

[barthbradley]

Convert to Sketch and modify the boundary/risers.  

[syman2000 · Accepted solution]

When you convert to sketch, you have to make sure you define the external boundaries (green lines). Then the riser line (black line) needs to intersect with the boundary lines.  

[ToanDN]

You are using boundary line (green) to draw steps.  Use riser line instead.  Boundary line is only for the outside left and right edges, not for steps, not for start and end edges.

[Claire_AlgarinEVZUB]

Thank you! I hadn’t extended the riser lines. I drew the run boundary and assumed the risers would extend automatically.