04-22-2021, 03:39 AM
Yellow question answer
No. You accidentally stuck the caps to the vanishing point governing the sides perpendicular to these caps. This vanishing point will help to determine how the squares containing the caps should shrink (by helping to locate the corners aka vertices) but they won't give you any of the 4 edge outlines of these cap squares. To put it in a different way, you can't draw a line from this VP to outline any side of the caps' squares. This happens because all lines originating from this particular VP create a 90º angle with the cap squares; any line coming from this VP is only able to only touch these perpendicular squares once. It might help to visualize those lines as something puncturing these perpendicular planes.
You seem to be instinctively aware something was amiss or you wouldn't have asked the question, and my advice at this point is to build the box then draw the caps. Don't move onto the ellipses until you have the box. Once you get to the point of instinctively knowing how VPs relate to a given side then you can start to change the order you do things and skip stuff.
Here's a stinky 3D compilation of a cylinder inside a box that hopefully helps to drive this "shape inside a box in perspective" point home:
Red question answer
I'm not sure I understood the question. Don't you already know the VPs since you used them to draw the boxes? This would be a matter of drawing a line from the centers, which you found, to them.
I should mention I'm excessively lazy and didn't check the 250 exercises page to get their full context so this might be the source of my confusion. :x
No. You accidentally stuck the caps to the vanishing point governing the sides perpendicular to these caps. This vanishing point will help to determine how the squares containing the caps should shrink (by helping to locate the corners aka vertices) but they won't give you any of the 4 edge outlines of these cap squares. To put it in a different way, you can't draw a line from this VP to outline any side of the caps' squares. This happens because all lines originating from this particular VP create a 90º angle with the cap squares; any line coming from this VP is only able to only touch these perpendicular squares once. It might help to visualize those lines as something puncturing these perpendicular planes.
You seem to be instinctively aware something was amiss or you wouldn't have asked the question, and my advice at this point is to build the box then draw the caps. Don't move onto the ellipses until you have the box. Once you get to the point of instinctively knowing how VPs relate to a given side then you can start to change the order you do things and skip stuff.
Here's a stinky 3D compilation of a cylinder inside a box that hopefully helps to drive this "shape inside a box in perspective" point home:
Red question answer
I'm not sure I understood the question. Don't you already know the VPs since you used them to draw the boxes? This would be a matter of drawing a line from the centers, which you found, to them.
I should mention I'm excessively lazy and didn't check the 250 exercises page to get their full context so this might be the source of my confusion. :x