Mantra error loading Geo issue

[Joshmjc]

Hey guys, I'm trying to render out a pyro by combining caches together. However when I go to render it just gives me the error - "Mantra: error loading geometry obj/cache_setup/merge5 from stdin

Any ideas? I've forced objects in the mantra node and the lights. It shows in the render view just doesn't do anything when I hit Render to Disk.

 

Thanks!

[fathom]

you'll have better luck not merging and just having multiple objects set up as packed disk primitives (from the file sop).  the merge really just adds memory overhead to your task.

[Atom]

It is probably a file name issue. Sometimes it is related to the frame number you are on. You may not have a frame #0 in your sequence, for instance. Look for missing or mis-named files in the folder that holds your sequence.

Edited April 20, 2016 by Atom

[Joshmjc]

Thanks for the advice and help guys, for some reason it magically worked when I loaded up the scene today. And the render time was faster. I have no idea what happened at all.

[ftaswin]

Can someone elaborate more about this please? I am having the same problem rendering on the farm with deadline 8. Very annoying because it only happen on certain frames on random slaves. The only clue from the log was cannot load object from stdin. 

[TheDude]

without properly combining volumes, just merging multiple volumes can be a bad idea. for example if you have 2 seperate volumes each with primitive names "density" "vel.x" "vel.y" "vel.z" the shader won't necessarily know properties to apply to competing fields. It can just cause horrible problems. To "merge" volumes, you can use vdb combine or volume merge

[ftaswin]

Thanks for the tip. I am dealing with one density volume. However i was testing with some bgeo.sc geometries, alembics and the test pig with the same random error. It seems to be upset when reading geometries from disk but then sometimes i got error just from a mountained box

[Atom]

There is also the dreaded disk drive failure which can cause this problem too. If you can see the file on your disk try copying it to a new location. If your disk is ok, the copy should work. If you have disk drive failure you may get read errors.

Edited November 13, 2016 by Atom

[bunker]

You don't always have to merge the volumes, an easy fix for the multiple vel/density fields is to create multiple nodes on /OBJ/ level.
If your files are in a logical sequence ( fire_1.$F4.bgeo.sc, fire_2.$F4.bgeo.sc, ...) you can use opdigits() to copy the node number to the file path (attached HIP)
eg: `opdigits("/obj/render_fire_1")` will return "1". If you have more complex file names, a simple python script can create those nodes.
also your File SOPs can be set to Missing Frame=No Geometry, so they don't stop Mantra renders if a file is missing.

 

 

opdigits.hipnc