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=== Simple ===
[[Image:JmolStick.PNG|left|thumb|Fig. 7. Stick model of caffeine drawn in Jmol.]]
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In early displays only vectors could be drawn e.g. (Fig. 7) which are easy to draw because no rendering or hidden surface removal is required. 

On vector machines the lines would be smooth but on raster devices [[Bresenham's line algorithm|Bresenham's]] algorithm is used (note the "jaggies" on some of the bonds, which can be largely removed with [[antialiasing]] software.)

Atoms can be drawn as circles, but these should be sorted so that those with the largest z-coordinates (nearest the screen) are drawn last. Although imperfect, this often gives a reasonably attractive display. Other simple tricks which do not include hidden surface algorithms are:
* colouring each end of a bond with the same colour as the atom to which it is attached (Fig. 7).
* drawing less than the whole length of the bond (e.g. 10%-90%) to simulate the bond sticking out of a circle.
* adding a small offset white circle within the circle for an atom to simulate reflection.

Typical [[pseudocode]] for creating Fig. 7 (to fit the molecule exactly to the screen):

 // assume:
 // atoms with x, y, z coordinates (Angstrom) and elementSymbol
 // bonds with pointers/references to atoms at ends
 // table of colours for elementTypes
 // find limits of molecule in molecule coordinates as xMin, yMin, xMax, yMax 
 scale = min(xScreenMax/(xMax-xMin), yScreenMax/(yMax-yMin)) 
 xOffset = -xMin * scale; yOffset = -yMin * scale
 for (bond in $bonds) {
   atom0 = bond.getAtom(0)
   atom1 = bond.getAtom(1)
   x0 = xOffset+atom0.getX()*scale; y0 = yOffset+atom0.getY()*scale // (1)
   x1 = xOffset+atom1.getX()*scale; y1 = yOffset+atom1.getY()*scale // (2)
   x1 = atom1.getX();  y1 = atom1.getY()
   xMid = (x0 + x1) /2;  yMid = (y0 + y1) /2;
   colour0 = ColourTable.getColour(atom0.getSymbol())
   drawLine (colour0, x0, y0, xMid, yMid)
   colour1 = ColourTable.getColour(atom1.getSymbol())
   drawLine (colour1, x1, y1, xMid, yMid)
 }

Note that this assumes the origin is in the bottom left corner of the screen, with Y up the screen. Many graphics systems have the origin at the top left, with Y down the screen. In this case the lines (1) and (2) should have the y coordinate generation as:
  y0 = yScreenMax -(yOffset+atom0.getY()*scale) // (1)
  y1 = yScreenMax -(yOffset+atom1.getY()*scale) // (2)
Changes of this sort change the handedness of the axes so it is easy to reverse the chirality of the displayed molecule unless care is taken.