What you´re calling "hairline cracks" is the pixel padding that gets applied after the bake. http://wiki.polycount.com/wiki/Edge_padding Without the pixel padding you would see normal map seems on texture mipmaps.
Have you tried rendering at 2x or even 4x of your final resolution? You seem to be doing everything right, it's just pixels being pixels, and MR has chosen an unfortunate way of drawing that ceiling line.
I think I have two issues here 1. Stencils(such as number, icon...) are pixelized. 2. The manual paper texture on the yellow plastic shell is also pixelized because texture size and uv map are not matched.
one last thing, if you're rendering out much larger maps than you need, make sure you have LOTS of pixel padding, i usually do 8 pixels at 2048, but you may want even more than that.
Is there a plugin or tool I'm unaware of that will display how many pixels x and y (2d) a currently selected object is on the screen? I'm working on some manual LOD's and the engine works on the pixels shown to switch to each detail level.
Yes, it's very easy to do. All you need to do is enter in the resolution you want in the capture settings. DPI is pixels per inch, so if you need to print 10 inches wide, you would render a 3000 pixel wide image.
Yes, packing UV's closely means you're getting more pixels on your model and less wasted in the gaps between. keeping a small 4-8 pixel buffer between UVs though is recommended so you can have that space for edge padding.
this basically. just don't buy ram from apple, they overcharge it a lot. "A 2880x1800 pixel display would have a density of about 220 pixels per inch at a 15.4" size," hating apple rn, my 15" mbpro is less than a year old :<
40"? I think I must have a different philosophy on monitors. I'm running a 23" (2048x1152) and a 21.5" (1080). The pixel pitch (size of the pixel) is tiny. I absolutely love the sharp picture, I can play without Anti-aliasing on at times.
Probably fine to use 48x48 for both. Best way to know is to test on a tablet. Do some research... What resolution is the tablet? Etc. But either way, the end result is pixels not vectors. PNG is pixels only. Use whatever software you're comfortable using.