April 23, 2003 Exhibit 16.1 Securities and Exchange Commission Mail Stop 11-3 450 5th Street, N.W. Washington, D.C. 20549 Dear Sirs/Madams: We have read Item 4 of 3D Systems Corporation's Form 8-K dated April 23, 2003, and agree with the statements made therein. Yours truly, /S/ DELOITTE & TOUCHE LLP