Hi Charlie, The Chimera 1.2199 C++ header files for Mac 10.4 are now on the source code page: http://www.cgl.ucsf.edu/chimera/sourcecode.html The 1.2199 Chimera Mac build was made on Mac OS 10.4 targetting Mac OS 10.3.9. I think this simply involves adding option "-isysroot /Developer/SDKs/MacOSX10.3.9.sdk" to your gcc or g++ compiles. Here are examples linking an object file and a shared library: g++ -isysroot /Developer/SDKs/MacOSX10.3.9.sdk -O4 -Wall -Wno-long-double -I../_volumearray -I. -I/usr/local/src/staff/goddard/builds/mac-10.4/chimera-2203/build/include -I/usr/X11R6/include -I/usr/local/src/staff/goddard/builds/mac-10.4/chimera-2203/build/include/python2.4 -I/usr/X11R6/include -DOTF_NO_FLOAT_MATH_FUNCS -DOTF_NO_SYMBOL -c -o surfmodel.o surfmodel.cpp g++ -isysroot /Developer/SDKs/MacOSX10.3.9.sdk -Wl,-executable_path,/usr/local/src/staff/goddard/builds/mac-10.4/chimera-2203/build/lib -bundle -bundle_loader /usr/local/src/staff/goddard/builds/mac-10.4/chimera-2203/build/bin/python2.4 -o _surface.so -O4 -Wall -Wno-long-double glstate.o smooth.o subdivide.o surfmodel.o surfrenderer.o write_x3d.o _surface.o Surface_Group_Object.o Surface_Model_Object.o -L/usr/local/src/staff/goddard/builds/mac-10.4/chimera-2203/build/lib -L../_volumearray -lrcarray _chimera.dylib -lwrappy2 -lotf -L/usr/X11R6/lib -lGLU -lGL -lX11 -lm -lm The /Developer/SDKs/MacOSX10.3.9.sdk directory comes from installing XCode 2.2 from Apple's web site. http://developer.apple.com/tools/xcode/index.html The Chimera Mac build now also contains universal binaries that work on PowerPC and Intel Mac machines. That was done by building Chimera on a PowerPC machine and separately on an Intel Mac and combining them somehow. I do not know how the combining step is done. Tom