3D modelling tool for CAD

[mazataza]

I have a plan to build an application which then used by artists to modelling basic building plans like in Autocad.
This tool will be used to help artists to draw their first proof of concept within it. thus it should be simple and complicated to used.
it should be as you take a paper and build the scratch of a building component like (room, walls between rooms, floor).
Because it should used in desktop and tablet i decided to use irrlicht as i can port it with less effort to android, iOS.
Thus I want some guidelines from those who have experience of building modelling tools.

I have created until now a grid and i can build a surface, but what what i don't know is how display guide lines for the surface to let the user later to modify it.
what I mean with guide lines are like showing the edges of a surfaces with their vertex as small box (in the build bellow showed as *).

*------------*
|
|
*----------- *

second problem is the surface edges are not antialiased nicely, may be after using material correctly and using texture is showed better.


I will appreciate any Ideas from u or guideline I should observe during development of such application.

[CuteAlien]

I'm doing something similar and basically my lines and the small boxes for the vertices are simply 2 different objects. One is a line (2 planes to draw a fat line usually) and the other is a box. Then each has a collision mesh which can be independently checked.

[mazataza]

the idea with the lines and square are a good idea.
the main issue here is to place the lines and the vertex above the surface so that it got drawn, or it will not be correctly drawn by the engine.

[CuteAlien]

You can experiment with the zbuffer material flags for that. Draw it last and use ZBuffer = false should probably do that I think (I also always need to test first to be certain). Or just use a second scenemanger for the stuff which is drawn above the rest and render that after the first one. Or just increase the height :-)