We deduced formulas for critical angles and areas that permit one to have an idea of the configurations of observed systems and to calculate their spectral energy distributions (SEDs) in accordance with their geometrical parameters and inclination of disks toward an observer. We present our results of SEDs calculations for a substar (M✶ = 0.02 M☉) with the disk (R_out = 8 a.u.) which is at a distance of 10pc and is tilted at angles of 0°, 20°, ...80° toward an observer. Using the algorithm proposed for the SEDs calculation, weperformed an approximation of observed fluxes from six substars with IR-excesses that are members of Upper Scorpius star forming region (usco128, usd160603, usd161005, usd161103, usd161916, and usd161939).