With both annual painting competitions (GothiComp and EpiComp) well out of the way, I thought it might be time to raise a question which has been troubling me for some time.
The question actually arose during the last GothiComp where I was appointed as one of the judges for the conversion category. As one would expect, each judge had certain preferences and we had a good discussion about pros and cons about each nominee before reaching a consensus and appointing the winner. An important issue that was raised was the question: What criteria are important to judge and what exactly makes a conversion "good"?
Let me first of all stress that this is in no way aimed at any entrant in any of the competitions. My quoted examples are purely for illustrative purposes, and a result of my personal opinion. As with any aesthetic judgments there's a great deal of subjectivity involved and I'm sure some people would disagree with me.
Anyway:
With 3D print available it is now possible to make pretty much perfect copies of larger models with a level of detail that is unachievable by traditional techniques (well unless your name is Will Hayes or Drasannar). I'm not mocking the effort that goes into producing a detailed 3d model, but it seems to me that the element of uncertainty that goes with handmade stuff (your hands may be shaky, the sculpting tool may slip etc.) a good conversion is also something about dexterity and craftsmanship.
As such I think that a good conversion must display a mastery of your chosen medium; that being plasticard, putty or whatever. The material should be formed by a human hand with the natural limitations that implies.
Secondly: The good idea! So, let's say that you are a skilled modeler. You build a BFG ship from scratch that looks just like the official model. Is that a good conversion/scratch build? From a technical standpoint, yes. From an aesthetic, no. In fact I think the good idea is a lot more important than craftsmanship. A conversion can be as complex as a complete scratch build, or it can be as simple as the addition of just the right part that nobody has used that way before. One example was USABOBs Gothic cruiser from last year, which featured a small cathedral from the Planet Killer attached to the bridge. It was a relatively simple conversion, but the idea was absolutely brilliant and characterful. Sometimes less is more.
Thirdly: Originality. Is the conversion "new"? Again using the GothiComp as an example: It is really that interesting to see yet another stretched Imperial Super battleship or Nurgle ship with tentacles all over? Personally I find it a lot more interesting when people throw known designs right out the window and tries something completely different. Sometimes it works, sometimes it doesn't but at least it is refreshing. You can then begin to argue if the design is within character of the army, but I don't think that's usually much of an issue. A good conversion in my book should "surprise" in some way. Be it a clever use of bits, a striking design or something else.
Finally: Aesthetics. Now this is a highly subjective area to move into and it is probably impossible to make even remotely objective criteria here. What I'm trying to aim at is this: Does the model "work". I.e. is it balanced, dynamic, are the parts integrated, in other words: Does this look like a completely new model/design and not just two kits bashed together? Obviously this is the final judgments that sort fuses the previous criteria.
The tricky part is deciding how much each criteria should weigh against each other. For example, one year a guy submitted a scratch built Space Marine cruiser that was so well made that I had mistaken it for a standard GW model until it was pointed out to me as a conversion. Very impressive craftsmanship, but the overall design was just so subtle that the model didn't have that "thingâ€Â
Orks are fun to convert because their vehicles are looted cobbled together. Getting that "Orky" feel is a blast ! 
