Is it OK to be mapping on multiple similar projects at the same time?

I'm wondering if it's good custom to be building multiple maps at the same time, instead of concentrating to finish one. Isn't there too much risk of losing focus, by starting a new map every time?

Depends. How many conflicting ideas can you manageably separate and work on? Are you working on them in the same day or not? Are the themes totally different? What works for me is one main project (newgothic right now), and maybe 1 or two side projects every so often (on and off with pcorf's wad, 1994 challenge, some speedmaps, something else I'm probably forgetting). Basically alternate working on projects such that it doesn't take all your waking thoughts (which it shouldn't anyway, that's unhealthy ;) and you can switch over when you finish a manageable goal.

I'd advise against it. I've got 4 projects on the go and I'm not making progress on any of them.

I'd say although both multiple projects and multiple maps can get unmanageable, it's almost better to have more than one project. But this is just my personal taste - when mapping, say, a multi-level wad, I try to mostly finish each map before moving on to the next one. I really only leave things like difficulty settings, multiplayer compatibility, and other tweaking for later.

Why not? When you run into a block in one project, switch to another. Meh, it's a hobby after all.

Pretty much what Gez said. It can be nice to have another project on the back-burner to go to when you run out of ideas while working on another. Of course it's probably not a good idea to go project crazy either, unless you plan on work on them for decades at a time :P. And it really all depends on how well you can focus on multiple things too. I can't multitask to save my life so I generally will focus for a while on one project, take a break, and then focus on another project for a while. I'd have hard time working on a map one day and then jumping into another entirely different map the next day.

I think it depends on how long you can concentrate on one level with one set of ideas for it. My attention span is about 6 minutes, so I get bored easily, and move on to something else. There're currently 11 maps on the go for mu wad but they're all sufficiently different to keep working on.

Rotating through your efforts keeps things fresh.

I hit a brick wall with every project I work on, I've just started another map for E1M1. I think working on two projects at the same time is fine, having too many projects going will drown you in work. And some of it will probably never get finished. When getting stuck with progress on a map do something else than mapping, play a game or some other doom maps.

When I tend to lose ideas I noticed my mapping habits change to copy and pasting and adding nothing but symetrical rooms. Mappers block can really drag on for weeks, and I usually get it after finishing a map.

It ends up being more down to you and the time really. Sometimes having lots of things on the go works for me if they're small, other times a huge sequence of work on one project is where it's at. Most of the time though, I get nowhere. I've probably cancelled more projects than I've released by now, and I've got a few that may well join them at some point.

I think it's best to keep focused on one project at a time. Especially if it's a group effort. Being focused on your one project lets your other group members know you are dependable.

Thats not how I map. If, for example, I wanted to build a space station map then I would focus entirely on that map, I wouldnt play any other wads that didnt have the same theme as my level and I wouldnt even think of starting a new project until I'd finished the current one. Otherwise If I started to create a Hell map then I would lose interest in the space station until I just stopped working on it completely and then of course, the cycle would begin again. I guess thats another reason why I try and map fast because otherwise I will just get distracted.