Rendering a knob (odd pixel number)

Hello everybody,

since I am relatively new to Blender I must apologize in advance if the answer to my following question is obvious.

I am trying to build a knob for a NI Reaktor instrument and I have managed so far to construct it, to select the materials and so on. Is there a possibility to render a round object in a way that you get an odd number of pixels in the ouput file?

Please take a look at the attachment. Rendering a knob I always get an even number of pixels in the x and y direction, fo example 36 px (1), 38 px and the like. When you try to design an interface you can’t get a proper alignment of the GUI elements with an even pixel number. You need to have an odd number of pixels to place an interface element correctly - for example 37 px (2). Only with a number like that you have a x- and a y-axis meeting in one point at the center of the knob.

I have tried different camera distances, different lenses, orthographic and perspective view rendering, but the problem always remains the same. Of course you can rescale the knob in Photoshop after rendering but that worsens the image quality to an undesirable degree.

Any comment will be appreciated.

Thanks in advance, Alex


Hello al_h.

You’re not making a 3D model. While this may be doable with Blender, why not use the appropriate tools?

Hi ManOfSteel,

thanks for your reply. I am aware that I am not making a 3-d model in the strict sense of the word, and the links you provided are indeed very helpful. Thanks a lot. But do you know, how to get Blender doing the thing I tried to describe? I think the guys at Native Instruments must have been using a 3-d modelling program for their own creations. Just have a look at - well for example - the knobs of Massive. The shading seems to imply that a 3-d modelling technique has been used.

Thanks again. And thanks in advance for any other advice. - Al

well, instead of resizing in photoshop, you could just chop off a line. I didn’t know that Blender can’t render out odd pixel sizes.

As you can see here and here, a raster-based application can make 3D-looking images. How about this Game Boy?

And Blender can render odd pixel sizes. Scene > Render buttons (F10) > Format. Change X and Y to 55 (0x37), render and save the image. It’ll be 55x55 big.

Hi ManOfSteel,

you’re not affiliated with Adobe in any way? :wink:

To be earnest, the GameBoy example is really impressive. Thanks for sharing this tutorial. And thanks for the advice setting the format to odd values. This just solved my problem. I formerly used a 200 x 200 px format and rendered only a small cut-out (I selected “border”) depending on the border through the camera view. So thanks a lot. Blender is a wonderful application, especially when you have to interpolate the different positions of a knob … you can do that in Photoshop of course, but I thought it to be done more elegantly in a 3-d application …

all the best, - Alex


Nah, use the GIMP whenever you can. :wink: Seriously, it does most of what Photoshop does and it’s free, in all the meanings of the term.

You’re welcome. Good luck with the instrument.

Thanks again! Alex