I am working with some architectural plans in JPG and TIF trying to scale them to 1:1 inside Rhino.
I have a TIF file of the original plan that I want to use as scaling reference.
I then edited other plans (cropping, background, square ratio, etc) and have them as JPG.
When I import the TIF file, which is 9654x9654 pixels and choose 1 to 1, it gets one size.
When I import the JPG file, which is also 9654x9654 pixels and choose 1 to 1, I get a different size.
This means I can’t use the TIF file as reference to scale my JPG.
Why do these two images get different sizes despite having same pixel dimension?
Ideally I would want to use my original/unedited TIF file as reference, which does not have a square format, it is 9564x7616 pixels.
I get all these different sizes when using 1 to 1 option. I guess resolution has something to do with it.
But honestly, I don’t understand why I get such a big difference from my landscape JPG to a squared JPG. It makes no sense.
These are all imported as 1 to 1 with Picture command.
Edit: It is obvious from the screenshot that I should be using the ‘squared reference jpg’ to scale my other plans, I just wish I could use my original unedited tif file…
Hello - 1:1 uses the image’s ppi setting - usually 72 or 96 - to determine the 3d size of the plane. Higher ppi will make smaller planes. If there is none, I believe it will use 72 but I am not certain. Hm - my test here indicates it uses a larger number than 96 if there is no ppi in the file.
Most (if not all) image editors allow you to manage the resolution, so just make sure all your images are using the same value (typically 72 or 300 pixels/inch) and they will import consistently.
My general take on this is a bit different. If these are dimensioned drawings, the best way is to first get the Picture into Rhino and then scale it according to a known dimension. If the plans have been printed and then scanned, they will almost certainly not be accurate in both dimensions, so it may even be necessary to use Scale1D to correct stretching. In extreme cases I have had to rebuild the picture plane surface with more knots to be able to point-edit to correct non-uniformly scalable distortions.
If the images are screenshots from a CAD program they are probably reasonably accurate (as opposed to scanned prints), but it still takes only a minute to set up the correct scales and that way you are sure of what you have.
I finally figured it out! This was entirely on PS side rather than Rhino. The TIF I am working with had a PPI of 400 and PS did not let me edit it non destructively (options were grayed out). I also had no option to Save As JPEG. I ended up Exporting as JPEG. It seems that exporting in PS strips resolution metadata altogether. It is ppi-less because it’s not needed for screen use, only for print, thus is PPI is the default one by system, sometimes 72 sometimes 96.
Instead of exporting I changed mode inside PS to Grayscale and than made the grayed out options available, so no change in resolution when Saving As.
Thank you for the insight @Helvetosaur. I am working with scanned dimensioned drawings, but they are accurate enough, they are part of a library archive.
The edition I am undergoing does not have to do with the accuracy of the scale, but rather presentation. I need to clean the background of the drawings and give them all a square proportion. These are the drawings that will then be imported into Rhino and scaled to 1:1.
