Helical features are supported in the latest Solvespace release (3.0pre3). There has been some discussion of how chamfers, fillets, and draft angles might work,

Helical features are supported in the latest Solvespace release (3.0pre3). There has been some discussion of how chamfers, fillets, and draft angles might work, but the concensus has been that they would be tricky to add, and are not a priority for release 3.0.