Way back in June I tackled this group of cans totally freehand, using the contour approach, and wow but the results were pretty bad! It's actually hard to believe that I drew this but at least the sketch suggests that I've improved in the last couple of months. Either way I knew that I could do better and figured that the grid method might help me:
With the lines in place on my pad I set to work determining where I could positively identify features (such as contours crossing a grid line) and noting them down. This very much gave me a sense of how the objects really arranged themselves rather than how I imagined them to be. For example the effect of perspective is huge here and the sides of the cans are very far from being parallel; in fact they pull towards each other markedly. For the same reason the tops of the cans appear far larger than the bases and in a way are quite distorted:
Fortunately the grid lines demonstrated that I was on track and I managed to put aside my expectations of what I was drawing and let the contours be my guide. As you can see this led to a very respectable contour drawing which closely matches the arrangement. Now even though I probably won't be able to do so well freehand at least now I have a respectful understanding of what's going on for the future - and next time I won't just assume that all of the sides are parallel! A valuable lesson.