.. admonition:: **What if my protein is too big for a box size of 37x37x37 pixels?**

    Because TomoTwin was trained on many proteins at once, we needed to find a box size that worked for all proteins. Therefore, all proteins were used with a pixel size of 10Å and a box size of 37 pixels. Because of this, you must extract your reference with a box size of 37 pixels. If your protein is too large for ths box at 10Å/pix (much larger than a ribosome) then you should scale the pixel size of your tomogram until it fits rather than changing the box size. Likewise if your protein is so small that at 10Å/pix it only fills one to two pixels of the box, you should scale your tomogram pixel size until the particle is bigger, however we've found that for proteins down to 100 kDa, 10Å/pix is sufficient for the 37 box.
