> ### Setting the Materials

> In addition to the lighting effects, nice effects can be achieved by changing the material settings.
> The material settings of a representation can be modified using the Modify Representation dialog.
> Open it by pressing the right mouse button in the Representations window on the Ball and Stick representation built from the ARND peptide. Choose Modify Representation in the activated context menu.
> The Renderer box offers to switch between the three current renderes of BALLView.
> - OpenGL,
> - POVRay, and
> - RTFact.
> Click on RTFact in the radio button list and enable the automatic update checkbox.
> The best way to get to know the different material properties is to play with their sliders.

> #### Ambient Intensity

> The Ambient Intensity specifies the amount of background light that is unconditionally added to the represenation.
> Try different Ambient Intensity factor values and compare the change in the molecule's appearance.

> #### Specularity

> The Specularity determines the intensity of the specular highlights.
> Change the Specularity factor to a smaller value and watch the highlights.

> #### Shininess

> The Shininess accounts for the size of the specular highlights.
> Vary the Shininess factor and compare the highlights on the molecule.

> #### Reflectivity

> The Reflectivity is the ability of the representation to reflect light, i.e. to act as a mirror.
> In the following, we guide you to change an already added plane into a mirror.
> Open the Modify Representation dialog from the context menu of the mirror plane's entry in the Representations window (right click on the entry), select the RTFact renderer in the radio button list, and enable the automatic update checkbox.
> Now, set the Reflectiveness to 1.
> Close the dialog by pressing OK.
> Now, change the camera position to a viewpoint where both, the molecule and its mirror image, can be seen simultaneously.

> #### Transparency

> The effect of Transparency can be perfectly demonstrated using a transparent molecular surface.
> To this end, build an SES surface of our molecule by opening the context menu of our protein ARND in the Structures window (right click on it) and by selecting Create Representation. Then choose SES->by element.
> Open the Modify Representation dialog of the SES surface in the Representations window by opening the context menu of SES.
> Select the RTFact renderer in the radio button list, and enable the automatic update checkbox.
> Now, set the Ambient Intensity to 0.03, the Reflectiveness to 0, the Specularity to 0.14, the Shininess to 6.125, and the Transparency to 55%.
> Close the dialog by pressing the OK button.
> Enjoy the picture!
> Press Next to continue.