I'm no expert, but would be interested in Affinity if it were capable of producing product mockups like you can in PhotoShop. PS is difficult for someone like me, but if there were an easy way of applying, say book cover designs to photos of books with blank covers, and which deals easily with lighting effects, reflections and textures, then I'd be keen. Another example: apply a t-shirt design on a creased up t-shirt, so that the design maps onto the texture. I think there are psd templates in Photoshop for this kind of thing. Can it be done in Affinity?
