Hi Charlie,

Working on getting lowest possible resolution and maintaining the detail required.   I start with a canvas at 200 ppi, import an image, create all  my tool paths.  Save as a new file then I change the ppi in the canvas to 100 ppi and regenerate all the tool paths.  Even though the image was imported to a canvas at 200 ppi in the original file, will the tool paths be generated as if the image was imported at 100 ppi as that is what the canvas ppi is at in the second file.  Or should I be importing the image into the second file with the canvas set a 100 ppi - creating a new file from scratch at 100 ppi?

Doug

Hi Doug,

The canvas resolution doesn't affect the loading of raster (pixel-based) images as raster-layers. They will retain their original pixel data when composited with the canvas. The canvas resolution only affects when an SVG vector image is loaded as a raster-layer, as it determines the number of pixels in the resulting raster-layer.

Basically, when you load an image as a raster-layer, it doesn't matter what the canvas resolution is. The canvas resolution only affects the resolution of the canvas as a whole but not the contents of layers that are being composited onto the canvas.

If you load a large high-resolution image it *might* get downscaled a bit just to keep things quick, but not usually in any noticeable way. It's just to avoid unnecessarily expensive compute. 

Toolpaths are generated from the canvas composition as a whole, where all of the layers (except paths-layers) are combined per their blending modes, origins, and dimensions, at the canvas' resolution. The contents of a raster-layer are not themselves affected by the canvas resolution. You can think about the canvas as a "camera" that's just capturing the state of the layers within it, and whatever that camera captures is what toolpaths are calculated from - but raster-layers themselves are independent of this camera with their own resolutions.

Text-layers and model-layers are rendered at the canvas resolution, so whenever it changes so do they. The only "permanent" effect that the canvas resolution has is when generating raster-layers from a paths-layer. That occurs at whatever the canvas resolution is at that time and increasing it after the fact will not re-calculate the raster-layers produced using functions like Shapes From Paths, Sweep Paths, Raster/Text Along Paths, Stroke Paths, etc... They are generated at the canvas resolution and don't change with the canvas resolution being changed after the fact.

I feel like I could probably explain it more clearly but hopefully you got the answers to your questions in there somewhere :)

 - Charlie