This guide explains how to perform an optimal opacity setting according to the active rendering modality.
Making the biological structures transparent, digitally acquired inside their complex world, allows us to see through the objects in the foreground. The contribution of the voxels in front of you, referring to your point of view (camera view), is reduced compared to their real intensity value. The reduction of intensity is obtained by editing the opacity coefficient accordingly to our visualization needs.
This operation is defined as the single voxel's intensity values mapping vs. the opacity coefficient. However, this allows only a limited selection of the structures in the dataset, like specific structures or anatomical regions, since no spatial or specific information is considered. Since the structures do not just differ by intensity values, opacity is not suited for the selection or identification of objects in a dataset but only to improve visibility.