Why are the dimensions of an object missing sometimes. See the dimension on the right in the picture
Why are the dimensions of an object missing sometimes. See the dimension on the right in the picture
The dimensions are likely not missing--just covered up or outside the field of view. Remember you're viewing in three dimensions; at certain angles, objects (dimensions) next to each other can be obscured. In other cases, you may be zoomed in too close. Try zooming out a bit, and/or changing your viewing angle slightly.
The best dimensional control can be exerted by using the RULER tool.
The Ruler is a horribly implemented tool that really only finds the center of objects which isn't very useful. I want to know actual dimensions of the WHOLE object, like say a hole in a flat plane, not just things Tinkercad decides are "useful".