kyngchaos

In my experimentations for converting Illustrator files to Affinity, I find that SVG has a better potential than PDF.  PDF has some crucial limitations in the PDF format that are no good for complex technical drawings (I'm a cartographer):
- only top level layers are supported in PDFs (or at least Illustrator can only save top level layers as PDF layers).  Most of my AI files have at least one level of sublayers.
- within top level layers, sublayer content is not even grouped, so there is no way to easily recreate those sublayers.
- symbols are expanded to raw artwork.  Maps use symbols a lot and symbols must transfer without needing to be recreated.
- effects beyond basic transparency are expanded to raw artwork (ie simple artwork plus a rasterized shadow under it).  This is more easily recreated since most effects are the same within a layer.  Though the simple artwork seems to be split to separate stroked and filled objects (identical path geometry), a bit messy there.
- in some cases beyond effects, some artwork is still split to separate stroked and filled objects with identical path geometry.
I've found that SVG supports all that much better, though with other limitations of its own (but more easily dealt with).
- Layers
SVG has no concept of layers, but Illustrator exports layers as named groups.
So far, Affinity only converts top level named groups to layers.  Named groups in those top level layers are left as named groups.
Also, if there is only one object in a named group, it is not added to a layer, but imported as a lone object.
I suggest Affinity import any named groups as layers and sublayers.  And to ALWAYS make a named group a layer, even if there is only one object on the layer.
- SVG supports symbols, and Illustrator does create SVG symbols on export
But, Affinity expands all symbol instances, AND creates a separate expanded symbol of the symbol definition at the artboard 0,0
Please import SVG symbols as symbols.
- Masks
Affinity ignores masks on import - a mask is not created, AND the masking object is completely dropped.
Please support importing and applying SVG masks.
- Effects
Well, no suggestions here - it appears Illustrator expands effects for SVG export also.  Including splitting fill and stroke to separate objects.  This one will still need some repair work after import, or preparation before export.
 
These improvements will greatly help bringing over Illustrator files to Designer.