Camera view extents do not equal the rendered view extents. As far as I know, the program will fit what ever aspect ratio that is specified within the view window. Is your monitor a 21:9 aspect ratio? If so, I'd say Size to 3D window was selected for the render size of the Sketch. I've never used "Sketch" so I might be something in how it works...
ps. That monitor aspect ratio bit is a bit off as I'd expect to gain horizontal not lose vertical...
pss. You can turn on the Render Safe Frame in order to see the area that will be rendered based on the current render settings.
You say they are both sized A3, at what DPI? Maybe you are hitting max resolution for the sketch engine.
If you are at 300 DPI, try going down to 200 or 150. 200 DPI should still print fine on a decent quality printer.
Also check if you are starting the render with 3D window active, sometimes if you render 'from another render' (the last rendered image as active window), the 3D window will bug out a bit and do a zoom just before you render.
And make sure 'apply render safe frame' is checked.
Finally: do not resize the 3D window or render on two different machines, as this might also give different results for the camera view.
I'm assuming that even though you say "camera render", you mean that you set up proper (3D) Views from the camera where one view saves the Sketch render settings and the other saves the Cinerender settings.
My guess is that the pixel dimension ratio is not the same for each view / engine.
See the attached showing the size tab of the render settings. The 'render safe' area is based on the ratio of the pixel dimensions - not their absolute values. Even if you have to use lower DPI (total pixels) as Erwin suggests (I'm not sure this is true?) - the RATIO of width/height for each render must be the same in order to render the same actual area.
Anything not in the 'render safe frame' is 'clipped' (ignored), as you've seen. From what you show, the RATIO of the width/height for the render settings is different for the two engines in your setup.
Hope that helps.
PS Please never post the same question in more than one thread. It makes extra work for us moderators to move everything back into one place. 🙂
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