I'll just start by saying that I have indeed tried the "built-in" "Export Paths to Ai" option and followed-through by changing the view mode in Ai to "Outline" but the document is still empty.
I have Photoshop CS6 Extd. and Illustrator CS6.
My Photoshop design is made up of strictly paths, shapes, and text--no rasters. It scales fine indefinitely within Photoshop because everything is a vector. I've tried opening my PSD in Ai but all the layers are flattened--no paths. I could try selecting each layer in Photoshop manually and exporting them one by one. But my design has nearly 50 layers, even if I made an action that does not seem proper whatsoever.
Are these two products not compatible, or am I missing something? What can I do to export my vector design in Photoshop to Illustrator?
Here is a sample PSD file that is of identical properties: https://drive.google.com/file/d/0B9ip8MnSNo8CTWNWbTVvWExSRkE/view?usp=sharing
Through trial and error I found out that workflow between Photoshop --> Illustrator does not work nicely with "Color Overlay" if it is used as a layer style.
Additionally, I found that it is possible to easily retain a text layer without converting it to a shape. This will leave the text edit-able within Illustrator.
Thus, one may simply open a PSD file in Illustrator (using same versions, I have only tried with CS6) if your Photoshop document is free of all forms of raster-based art. For instance, one must be careful not to have any layer blending modes applied, layer masks, or layer styles as they all impede the math-based vectors from opening in Illustrator without flattening occurring.
Something else to consider is verifying your document for accuracy once successfully open in Illustrator. My project had some either improperly applied, or missing "Fills" and "Strokes."
When you open the exported file in Illustrator, it will most likely group all your shapes under one layer (make sure you go into the "Layers Panel Options" in the Layers tab and you have "Show Layers Only" unchecked? If not you won't see all the shape layers.) Open up that layer and select all the shapes, then choose "release to layers" located under the layer tab menu.
Keep in mind that you won't retain any of the color information. They will be straight up paths. Also, if you want to bring over any text, be sure to make it a shape before exporting. Hope this helps.