Consider setting, and exporting, the LD_LIBRARY_PATH=[absolute path to directory containing libraries] or LD_PRELOAD=[absolute path to specific library] environment variables in a shell script that is called before the pyrogenesis binary. See the manpage for `ld' at the documentation for the switch -rpath-link=dir for a description of the library search path order.
But, I haven't worked with AppImages before, so there might be reasons to not do this.
Also, you can use strace or ptrace to watch what directories are being searched for libCollada.so.
Search paths for shared libraries are configured in /etc/ld.so.conf.d/*
If you change the ld.so configuration then don't forget to run ldconfig as root to update the cache. However, changing such configuration might be an even worse idea, as it could have unintended effects on other binaries and libraries.