.DXF is definitely needed - affinity designer just doesn't work as an alternative to illustrator without it - it limits real world practical uses like lazer cutting or using 3D modeling software. Speaking as a former Architect - this software NEEDS to have this capability to stay relevant and be a competitor to Illustrator.
We have now added a spiral tool which is available from the shape tools flyout. This is something we have had many requests for, but also varying requests as to the type of result wanted. For that reason we have tried to make this as flexible as possible, both offering different types of spiral and variables to adjust.
When you create a spiral you will see from the context toolbar the different options available. Here are some examples of what you can create with the tool:
Spiral Type: Linear
Spiral Type: Decaying
Spiral Type: Semi-Circular
This type replicates the way many people have been creating a spiral in Affinity - effectively by joining decreasing semi circular arcs together. With this type we also offer a counter Semi-circular option which returns the spiral back on itself:
