Hi Sergey, You can use the Volume Path Tracer tool to put labels near parts of one or more density maps. Path Tracer is designed for putting markers on high density regions but it allows you to place them anywhere (in 3D), and you can put any label text next to a marker. The path tracer dialog is shown with menu entry Tools / Volume Data / Volume Path Tracer Start by changing some settings. Turn off "Place markers on spots with mouse". That is for placing marker on high density regions. Turn on "Drop markers on empty space with mouse". That allows you to place a marker anywhere, for example next to a density blob. Turn on "Move markers with mouse". This will allow you to reposition the markers and their attached label. Use button 3 with the ctrl keyboard key held down to place a marker. Click on the "Markers" button at the top of the path tracer dialog to see some more options in the dialog. Type in a "Marker note" and press Return to see it displayed next to the marker. The radius of the marker sphere can be made so small it is invisible (0.0001) but the value has to be > 0. The text can be given whatever color you want using the color button at the end of the dialog line containing "Marker Note". When changing marker note or radius you need to select it first in the graphics window (click on it or drag over it with ctrl button 1) so that it is shown with a green outline. To move the marker hold down ctrl while pressing button 3 on top of it and drag it. Holding down the ctrl and shift key lets you move it in and out of the screen. There is no control of label size or font currently although if you were saving an image you could make the Chimera window small so that the text is relatively large and use File / Save Image to save at whatever image resolution you want. Besides using labels you can of course give different density maps different colors to distinguish them. Use the color button in the volume viewer dialog for that. You can also color different blobs in the same density map with different colors. To do that you would place markers on the blobs as described above, give colors to those markers, and then use the Color Zone tool (menu entry Tools / Volume Data / Color Zone) to color parts of the surface within a give range of the markers to match the marker color. Lastly, if your blobs are not connected to one another you can do the coloring just by clicking on them using the prerelease "color surface pieces" features (http://www.cgl.ucsf.edu/chimera/prerelease/prerelease.html). Tom