The DICOM image can be read and rendered by using vtkResliceImageViewer. I want to draw region of interest(ROI) with the shapes like rectangle, circle(as the following picture show). After that, I want to modify the pixel of the slice image after drawing ROI and the 3D scene can get the 3D mesh of the ROI(with thickness). I have scaned the document and found the vtkContourWidget. It seem to be suitable for the requirement. But I am not sure, is there any more suitable class for me to use? I will be very appreciated if anyone can give me some tips. Thanks in advance.