KPovModeler (KPM) is one of the most complete modelers for POV-Ray available for GNU/Linux.
For most of the modelers, POV-Ray is nothing but a rendering engine and they bring a lot of limitations to the innate possibilities of POV-Ray scripted language. This is not the case for KPM which allows you to use all the features of POV-Ray through the translation of POV-Ray language into a graphical tree.
Almost all options of POV-Ray's script language can be used within KPM. "Almost" because variables, loop instructions, macros and some operators can't directly be, unfortunately. On the other hand, KPM allows you to include a part of a script with the "Raw POVRAY" tool; such a raw code will only be taken into account by POV-Ray during the rendering stage.
Among the features we could find :
For modeling an object, it is not required to know POV-Ray's script language. On the other hand, handling the textures is slightly harder because KPM lacks a texture editor like Truevision's: refering to POV-Ray's documentation will be difficult to avoid. Moreover, for some objects like lathes, objects parameters should be typed with the keyboard because the management of the object's shape through the use of the 3d view is not easy.
But to ease the work, it is possible to simply cut-and-paste a script from POV-Ray into KPM. KPM will then, if the script only makes use of known primitives, convert the pasted text and include it into the current scene. In other words, if you don't know how to create an object or an effect with KPM, you could always copy its example from POV-Ray's documentation and experiment with it within KPM.
Apart from these very few flaws, KPM is still one of the best POV-Ray's modelers available on any OS and the future versions will certainly deals with these youth flaws.