2.1 The Pen Tab
From 3D-Coat Wiki
Choose a pen you like from the list of pens. This is a list of default pens within 3D. You can add your own pens in TGA, PSD or ABR format (the pen format used in Adobe Photoshop). Press on the “Folder” icon to add a pen. The pen added will appear in the list of pens available. You can use a 3D model as a pen. A pen can be colored, provided the image contains alpha-channel. In this case the alpha-channel will be used as a mask for depth. Use CTRL or SHIFT to select several pens, you will see several pens selected in the preview, these will be used randomly.</p>
Choose a pen, set radius “20” and try drawing on the object. Increase radius, choose another pen shape and draw a bit more. Use “T” key quick access the pen menu. First press SHIFT and draw again. You will see the surface getting smoothed. Change the smoothing intensity using the “Smoothing” slider. First press and hold on LMB then press SHIFT and draw again. Then you are able to draw very straight lines just like the way in Photoshop. Click CTRL and draw – Cavities are drawn.
You can rotate your pen. Parameters of rotation range from 1 to 360 degrees. You may use hot keys “(“ and “)” or the mouse wheel (under correspondent settings in the Preferences menu) to rotate the pen counter clockwise or clockwise accordingly.
You can see the red line rotating on the pen cursor when “(“ or “)” is pressed. If you choose an asymmetrical pen shape then this rotation shows the pen orientation.