I can get Radeon ProRender, Arnold, and Renderman all opening up and rendering in the same Houdini session (Houdini 19.5.640 Py3.9).
When I check the About Houdini info in my session, it shows that all three packages are loaded from the correct dir (C:\Users\****\Documents\houdini19.5\packages) and the .json files all seem to be working fine.
I can render with all of the engines/delegates with basic geometry, but as soon as I try and render a sphere with a mtlx material (downloaded from the AMD Library) they all render it fine except for Renderman, which just spits a ton of jibberish to the console. If I remove the Arnold.json from the packages directory and restart Houdini, Renderman renders everything perfectly fine.
Is there a possibility that mtlx libraries are clashing? I have followed this blog post and even copied the arnold.json syntax into my arnold.json file https://www.toadstorm.com/blog/?p=722 [www.toadstorm.com]
It seems like PATH may be clashing, but it's set to 'append' in the Arnold json and 'prepend' in the renderman json... I've renamed arnold.json to zarnold.json so it loads renderman first (blog comments suggest they're loaded alphabetically). Still no success.
Attached my .json files. Here is the error log:
Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_multiply_16:out" was found for input "texcoord" of instance "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15" of plugin "c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx" on gprim "<unnamed geometry>".
R10043 default, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 file, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 filtertype, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 frameendaction, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 frameoffset, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 uaddressmode, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 vaddressmode, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_15).
R10043 index, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_texcoord_vector2_6).
R10041 Invalid or mismatched reference parameter "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/UVScale_Flakes:out" was found for input "in2" of instance "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_multiply_5" of plugin "c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx" on gprim "<unnamed geometry>".
R10041 Invalid or mismatched reference parameter "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_texcoord_vector2_6:out" was found for input "in1" of instance "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_multiply_5" of plugin "c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx" on gprim "<unnamed geometry>".
R10041 Invalid or mismatched reference parameter "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_multiply_5:out" was found for input "texcoord" of instance "/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11" of plugin "c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx" on gprim "<unnamed geometry>".
R10043 default, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 file, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 filtertype, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 frameendaction, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 frameoffset, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 uaddressmode, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).
R10043 vaddressmode, unknown or mismatched input parameter of c:\PROGRA~1\SIDEEF~1\HOUDIN~1.640\houdini\materialx\libraries\stdlib\stdlib_defs.mtlx (/Car_Paint/Materials/Car_Paint/NG_Car_Paint/node_image_float_11).