EXHIBIT 16.1 [LETTERHEAD OF DELOITTE & TOUCHE LLP] April 29, 2003 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 29, 2003. We have no basis to either agree or disagree with the statements made in paragraphs 1 through 4. We agree with the statements made in paragraphs 5 and 6. Yours truly, /s/ DELOITTE & TOUCHE LLP Deloitte & Touche LLP