   world coords problem
  hi,i just want to ask a couple of questions regarding the foundation of a 3d editor,most 3d editors come with a standard ortho/perspective toggle,there is also a cursor positioned within the world co-ordinate system,what is the best ways to move this cursor about by using mouse-clicks within ortho and perspective views,the way i have been trying recently is using gluUnproject, and while i can get the desired results for the near and far clipping with this function, i can't seem to get the desired results on the grid platform that i have built,the main reason is that my grid platform has its origin at 0,0,0 which means that some of it falls outside the nearclip, and gluUnproject only caters forworld coords within the scope of near and far-clip,if i translate my grid deeper into the viewport beyond the nearclip, then the center is no longer located at 0,0,0, and i would have to make adjustments for further drawing, however this means that it is well in the bounds between near and far-clip and i can use the z-ray to calculate other values of z that will fall on all points of the grid, and thus move my world cursor according to these....is what i am saying here even possible?making sense?please advise?from what i thought i understood the near-clip would merely clip anything falling oustide its bounds within the viewframe, so if i had a firstperson camera that could translate its position, i could bring things outside the nearclip into the view by moving backward, however the way i set up my camera is that it translates the modelview matrix, and not the projection matrix,this becomes a problem when using gluUnproject as it is somehow connected to the near and far clip that is set within the projection matrix,which the camera view is not affecting at all, and therefore my near/far clip results in gluUnproject omitting a portion of my grid......sorry i am getting completely frustrated withmyself trying to explian my point, i wish i could post a minimal code, but there is always the guilt and fear of being reprimanded for clogging the forum with code(would that happen?)..i seriously think if i posted some code i could get a better answer.anyhow if you can make sense of some of this please advise on a direction i could take....i just realised that i might be able to post an image which would explain my situation perfectly will try that.   