Exporting failed with unknown error

[vladimir.nedev]

For the 2015-04-17 nightly build, I've added a check at the beginning of the export process, that will make sure all items in the scene have valid identifiers.
This will prevent the internal crash during export.
If an item with an invalid ID is found, rendering is aborted and a message dialog will pop-up with a message:

"Item with invalid identifier found ! Rendering aborted.
Item name is : ..."

This will help you identify what referenced scene needs to be reloaded.

Greetings,
Vladimir Nedev

[kubbek]

The "Translating MODO scene to V-Ray" part depends on the item list complexity, the amount of unique material/part/selection tag combinations and the shader tree complexity.
What happens now is :
for each geometry item (including normal instances, but not including replicator instances)
---- for each unique material/part/selection tag combination in that item
--------- traverse the shader tree
The complexity of each of these get multiplied together.
I can optimize this by discarding geometry items and material/part/selection tags that are not used in the shader tree.

I don't have access to the "Power Translators" plug-in for MODO, but maybe there is an option somewhere to tell it not to import part tags.
Also I see there is an option to import the geometry as Static meshes. Static meshes can't have their material/part/selection tags changed
(so the 'm' key won't work on them, but you can still use items masks for them in the Shader tree), but they can be exported very fast to V-Ray.
I've tried it on your scene and manually converting all meshes to static meshes changed the "Exporting keyframe..." time from ~24 seconds down to ~0.5 seconds. Translation time is also reduced.
It also reduced the scene size on disc from 748 MBs down to 319MBs. When loaded into MODO the static mesh scene takes ~3GBs from system RAM,
with editable meshes it is ~10GBs. Also loading the scene into MODO takes ~30 seconds with static meshes, and 2m20s with normal meshes.

The static meshes have one huge disadvantage though - they render extremely slow in MODO's Open GL viewport.
My guess is they didn't get updated to use VBOs. This can probably be reported to The Foundry as a performance bug.

I removed all polygon tags and V-Ray export time difference is massive. Should also experiment with statich meshes.
Currently have no access to Power Translators as I used demo version for this experimental project. Probably I will buy it at some point - I will than experiment with its settings.

Also your scene has an insane (205) number of lights , so it may be a good test for the probabilistic lights option.
I tried rendering a region of the scene with no GI, with 8 probabilistic lights, it rendered for 4m.33s., without probabilistic
lights it rendered for 17m18s. I used our own ray acceleration structure instead of Intel's Embree, in order to preserve
some memory, with Embree the render time difference might be smaller.

I used probabilistic lights in my previous interior project but forgot about it this time. Surely it is the case where it should help substancialy.

For the 2015-04-17 nightly build, I've added a check at the beginning of the export process, that will make sure all items in the scene have valid identifiers.
This will prevent the internal crash during export.
If an item with an invalid ID is found, rendering is aborted and a message dialog will pop-up with a message:

"Item with invalid identifier found ! Rendering aborted.
Item name is : ..."

This will help you identify what referenced scene needs to be reloaded.

Greetings,
Vladimir Nedev

Great. That should help in this case.

[vladimir.nedev]

Can you give me a link to that "Power translators" demo, I can't seem to find it.

Greetings,
Vladimir Nedev

[kubbek]

Can you give me a link to that "Power translators" demo, I can't seem to find it.

Greetings,
Vladimir Nedev

You have to contact sales@thefoundry.co.uk and you will get a demo through your account. It is not publicly avaliable.

[vladimir.nedev]

You have to contact sales@thefoundry.co.uk and you will get a demo through your account. It is not publicly avaliable.

I see, thank you.

Greetings,
Vladimir Nedev

[philstopford]

I'm reviving this thread as it is the only one that showed up with a search. I've run into the same 'invalid identifier' error here with a referenced scene. I wondered if there was a way to make the referenced scene play nicely with Vray.

[vladimir.nedev]

I'm reviving this thread as it is the only one that showed up with a search. I've run into the same 'invalid identifier' error here with a referenced scene. I wondered if there was a way to make the referenced scene play nicely with Vray.

[ATTACH=CONFIG]34344[/ATTACH]

You can right click on the referenced scene and choose "References -> Reload Imported References".
Sometimes this will fix the issue.

This is a MODO bug, items should always have a valid internal identifier, so sending the scene to them might be helpful.
The invalid identifier seems to happen randomly, upon loading the scene, so probably pretty hard for them to fix.

Greetings,
Vladimir Nedev