How do you move vertices subtly?

Can anyone help, i have made the start of a 3d modelling programme but it is to turn into far more. However i have a slight problem when using the mouse to move vertices…

I can select vertices with the mouse no problem but when i try to use the mouse to then move the vertex the vertex jumps DRAMATICALLY making it unusable…

How do i get round this…presently i have the vertex coords being set, after the mouse has selected it and is still on it, to be wherever the mouse goes from that point on until the left button is released…please help (sample code is more than appreciated)


For anyone interested in replying or who can help…it was a silly mistake that caused the dramatic movement of a vertex, the real problem is that when i have say 5 vertices selected and i want to move them they all get moved to the same point as the mouse, but i need them offset according to their original location…any ideas?

Create a vector to the direction the mouse is moving and use this vector to move the vertices in that direction. That should do it.