{"id":307,"date":"2011-04-19T12:42:44","date_gmt":"2011-04-19T11:42:44","guid":{"rendered":"http:\/\/www.treeshark.com\/treeblog\/?p=307"},"modified":"2014-04-15T11:13:03","modified_gmt":"2014-04-15T10:13:03","slug":"the-problem-with-columns","status":"publish","type":"post","link":"http:\/\/www.treeshark.com\/treeblog\/?p=307","title":{"rendered":"The Problem With Columns"},"content":{"rendered":"

This is the second of an occasional series of posts about perspective. Many people believe that geometrical perspective, single point, two point and three point are actually an accurate representation of what we see. Cameras see in this way after all so it must be right mustn’t it? Well actually no, it is a compromise as are all methods of making our very three dimensional world fit conveniently on a flat surface. Here I am going to deal with a very old problem that perplexed Renaissance artists as they struggled to find solutions to the problems of illusory painting.\u00a0Vredeman de Vries and other artists published learned books full of geometrical construction but certain problems seemed impossible to resolve. Columns were a big feature of architecture of the time and they often occurred in long arcades, perfect fodder for the perspective method you would think. However it turns out that round columns are exactly the type of object that causes the neat geometrical rules to fall apart. What I intend to do here is highlight the issues as clearly as I can and then point the way to the various solutions that later artists arrived at. It is a sad fact that all modern books on perspective that I have seen do not even seem to realise that the issues are there, let alone giving any practical advice to overcome them.<\/p>\n

 <\/p>\n

.<\/p>\n

\"perspective,<\/p>\n

Here we have a plan view of a simple set up consisting of a row of columns, a cube and a green triangle which marks where our viewer is standing.\u00a0Below is what we get if we construct using one point perspective what that viewer would see.<\/p>\n

.<\/p>\n

\"perspective,<\/p>\n

Well here we are, at first glance it seems sort of OK. Look more closely though and we have some problems. In our plan we can clearly see that all the\u00a0columns are the same size. That does not however seem to be the case in our perspective projection. The column on the far left is a lot wider than the one\u00a0straight in front of us. Worse when we look at the plan the far left column it is actually further away from us and should appear smaller not larger. Something\u00a0is plainly awry. Looking more closely still the base of the far left column seems oddly tilted. This is exactly the result a camera would give on a fairly wide\u00a0angle lens giving a viewing angle of about 70 degrees. So when you wonder why you looked so fat in that group photo this is the cause and in future you\u00a0would be best to make sure you are in the middle \u00a0of the line! Lets take another case.<\/p>\n

.<\/p>\n

\"perspective,Here is the plan of a simple set up, as before the green triangle marks our viewpoint.\u00a0We often get rows of things receding from us, looking down a romanesque\u00a0church nave would be an example.\u00a0Below is how traditional two point perspective renders the scene.<\/p>\n

.<\/p>\n

\"perspective,<\/p>\n

Once again at a quick glance it all seems well but a closer one shows that the left column again shows problems. These are clearer still when we isolate\u00a0that part as in the green circle. There is a weird tilt which is plainly not how we would really see the base of such a column. If you then tried to\u00a0add capitols\u00a0and bases you would find it very hard to get them believable. Below is an example from an old perspective manual by Jan Vredeman de Vries\u00a0printed in 1599.<\/p>\n

.<\/p>\n

\"perspective,<\/p>\n

As you can see the problem is still present, and remains over the centuries up to the present day. This is because there is no right way to solve this problem.\u00a0Whatever we do it will still be wrong. The trick is to be pragmatic and make the unavoidable departures from how we really see the world as subtle as possible.\u00a0Lets look at the dilemma more closely.<\/p>\n

.<\/p>\n

\"perspective,<\/p>\n

Here is our old enemy the ellipse, I won’t go into how to construct one as there are many methods freely available on the web if you are interested.\u00a0In the real visual world as seen by our eyes when, for example, we look at a coffee mug on the table or any circle that is parallel to the ground,\u00a0the major axis of the resulting ellipse is always parallel with the horizon line. Try it, put a plate on your table and slide it around. But cameras and\u00a02 point perspective construction produce ellipses that have the major axis tilted. It is this that produces the odd distortions. All we can do is come up\u00a0with a compromise, a sleight of hand adjustment that is not perfect but improves the believability of our drawing.<\/p>\n

.<\/p>\n

\"ellipse,<\/p>\n

Here is a circle constructed in two point perspective. The problem is that cross and the ellipse with it need to be parallel to the horizon line to look right to the eye.\u00a0Yet at the same time it needs to fit into the blue box.<\/p>\n

.<\/p>\n

\"ellipse,<\/p>\n

Here is our compromise. The winners are the ellipse which is now properly aligned to the horizon and also a wee bit narrower to correct for the first problem of\u00a0“fattening”. The losers are the chequer board floor on to which the column no longer perfectly fits. But as you see the mis fit is quite small and far less worrying\u00a0to the eye in my opinion. Below is the correction applied.<\/p>\n

.\"perspective,<\/p>\n

It would be easy to tweak the lines of the floor to make the adjustment less noticeable, but I have left it alone as it shows where the changes have been\u00a0made. Returning briefly to the very first example of the over wide columns left and right one solution here is to make all of the columns the same as the\u00a0central one. Again a compromise that may throw up other problems but a good starting point. Chequer board floors of course make the whole problem\u00a0worse. When I was designing for television advertising I once put a chequered floor into a shot that was to be filmed on a wide angle lens. The cameraman\u00a0was not at all happy and the Director made me paint it out! The next instalment on perspective matters will be how to place arches, doors and windows\u00a0into buildings in a scene by a few rule of thumb tricks.<\/p>\n

Share this:<\/h3>