This is a good question that we are often asked. Today we give some helpful information about it.
Basically, Markforged 3D printers always use the same material for the support structure as for the part itself. For the plastic printers this means Onyx, Onyx FR or Nylon White and for the Metal X the respective metal (tool steel, stainless steel, Inconel or copper).
For plastic parts, the cloud-based slicing software EIGER builds the support structure in zig-zag lines under the areas whose angle is less than 45°. This structure is narrow enough to support the area above, but wide enough to break out like an accordion after printing. What remains is a slightly rougher surface on the component, which can be finished if necessary. We also have a small video in Youtube with the Onyx material: