If you've never done level design for Marble Blast before, then Constructor is the only way to go. It's the only one we recommend for amateur/beginner level designers. It is a lot easier to use, its options are good and it converts stuff *generally* without problems.
However, it must be noted it has some crazy glitches and bugs, likes to crash often (save frequently is an understatement) and depending on what you add to your level, may not even convert your map, lose polys for no reason and generally is a nuisance.
So why do we recommend it? because you can do lots of cool things pretty quickly, its 3D is very good and allows you to do certain things (especially with textures) much more easily that QuArK cannot do or is just slow at it.
Constructor-made levels won LotM/Year competitions, and is the #1 tool of choice for forum members.
What about QuArK? QuArK is strictly for Advanced or Professionals. Its learning curve is very very high and you're gonna have to learn it yourself, whereas with Constructor you have lots of tutorials and premade stuff, as well as on the forums. Once you do manage to learn it, you can pretty do what Constructor does and much more. Unless flexicubes are something you cannot live without or some of Seizure22's rotation/shapes tools, QuArK is the ultimate choice.
You can debug maps, find errors super easily, you rarely get crashes and it's very solid. It also supports dozens of other games, meaning it comes with more options than anything else. Making convertible curves, pipes and loops is trivial. You never have problems with triangles, so MBP scenery is easy. Floating point errors are non-existent (unless you use maps made in constructor) and it's generally awesome all around. The downside is that you're gonna have to do manual texturing and tex-wrapping.
Lastly, you can create packages that include textures, maps and others all in one file (think of Constructor's albums going advanced). If you've got plenty of experience of level design and want to go to the next stage, QuArK is yours.
QuArK has been used by professionals across many games, universities, even GarageGames when they created Marble Blast (Gold, Gold Xbox, Ultra). It's the #1 tool used by the top level designers, including Oaky, Pablo, Phil and myself. I suspect PF is a QuArK-convert
Therefore:
Quote:Which one converts interiors better with no glitches or errors?
Is the wrong thinking. Constructor should be your choice no matter what. It will do what you want, but QuArK is heaps better at having less glitches/errors, but you will get the exact same result in Constructor.
"matan, now i get what you meant a few years back when you said that "the level in mbg is beyond me" after the last rampage i noticed things were insane, and now i truly feel that too" - Dushine, 2015.