I am running an idl script that includes the below line in a for loop (million times). ENVI_DOIT, 'TOPO_DOIT', FID = fid, ELEVATION = elev, AZIMUTH = azim, $ BPTR = [2], DIMS = dims, POS = [0], R_FID = r_fid, $ PIXEL_SIZE = pixel_size, IN_MEMORY = 1 Above line calculates the shaded relief of a single pixel (only 1 line and 1 sample) at each time. Whenever I run this comment, idl pops-up a small rectangle window on the screen saying "Topo Modelling .. Input File= C:\..., Output to Memory"... This small window has the same size as the "cursor location value" rectangle window in ENVI.. However, I believe, this popping-up window process consumes too much time and slows down the entire process (practically the script never finishes). Actually I do not have any other computation but this line inside my for loop. I tried running this idl script under "command line" version of idl but this window still pops-up.. Is there a way to get away from this window while running my idl script? Thanks Ray Laymon,