Jump to content

Recommended Posts

2 things to try:

1) if you are exporting from rops, make sure your display flag on your obj is on, and your render flag set to the correct sop

2) I had problems with exporting 'empty' alembics before, I noticed that if I choose the first frame when there is some geometry as the start frame for the alembic, it bakes out all the geo. -- As you can imagine it is quite annoying trying to find which is the first frame when there is actual geo.

Hi peter. Can you maybe show your actions in a video? Or just explain the way you got your particles in maya? On all forums some can with just abc, and other just cant. Im one who cant get it whatever i try.

Thnx

Share this post


Link to post
Share on other sites

2 things to try:

1) if you are exporting from rops, make sure your display flag on your obj is on, and your render flag set to the correct sop

2) I had problems with exporting 'empty' alembics before, I noticed that if I choose the first frame when there is some geometry as the start frame for the alembic, it bakes out all the geo. -- As you can imagine it is quite annoying trying to find which is the first frame when there is actual geo.

Hi peter. Can you maybe show your actions in a video? Or just explain the way you got your particles in maya? On all forums some can with just abc, and other just cant. Im one who cant get it whatever i try.

Thnx

Share this post


Link to post
Share on other sites

Hi peter. Can you maybe show your actions in a video? Or just explain the way you got your particles in maya? On all forums some can with just abc, and other just cant. Im one who cant get it whatever i try.

Thnx

Well I'm not peter, but I can do a long drawn out example if you want...

In New Hip

Tab - Geo , Dive inside

Tab - Popnetwork, the new one

         Wire the file node into the first input, 

         When you press play you will particles get created from the first frame onwards.

Now change the start frame on the "popnet" to frame 10

         This will change the popnet to start later for our "bug" like scenario

Tab - Rop Alembic Output

         Set you it to Frame Range and set frame range from 1 to 20 don't need anything crazy to test.

Save your scene file... so you can use the default $HIP/output.abc

Now press Render....

         Abracadabra you have the "bug": Error Saving first frame /obj/geo1/popnetwork

So the "logic" to this bug, is something about alembic not being able to handle "empty geometry frames" so is some how an alembic fault that sesi does not have a work around for

 

So to "fix" this simple case change frame range back to 1 on the "popnetwork"

         Now press Render on the "rop_alembic1" and your geometry will spit out.

 

Alternative solutions to make the alembic rop work with a variable such as the creation of geometry.

         Set your "popnetwork" frame start back to 10

1. prior to the rop_alembic1 

         Tab - merge

         Tab - box

                  Set the scale on the box to .0001 in X, Y, and Z, this theoretically makes an infinitely small box

         Now wire the the popnetwork and the box1 into the merge1

         Wire merge1 into the rop_alembic1

         Now press Render, and it should magically work

lol... no # 2 solution. There is only derivatives. So you may not want this random box hiding in your scene, then you'll to do an npoints(opinputpath(".",0)) in a switch to fed this guy something. Alterntively you can make the box be at the centroid of the sim and you'll have to be creative about it, but if you do switch of the centroid of where your emitter is and then switch if off once there are points then you can have a half ass solution. My "luck" has been that a box .0001 so small won't be noticed in your maya scene file, and if it is please do a test render and check to see if any phantom points are flying through your scene, most render engine should cull out the abnormally small box

 

The second way to break this in some previous of houdini other than my current version of 13.0.371(def happens in my old 12.5) is to set the frame start on the "popnetwork" to 10

         tab - null1

                 Now set the blue display flag on this node

         Pres render and it will error out.

This one seems to be fixed thank god, in the latest version... In 12.5 there used to be a parameter called "Use Display Sop" The only magically logic for this rop acting different than Rop Geometry that we all so love, is that it acted like a /out/ network driver "rop" as opposed to the context aware sop. Which drove me f-ing crazy.... 

 

Hope this helps...

SIDEFXBUG_ROPAlembicOutput.hip

Share this post


Link to post
Share on other sites

Ok problem is still here in Maya 2016 :

// Error: line 1: particleShape1: Object not found for -object flag. // 

- you can export particle as abc from Maya to Houdini

- you can't read a Houdini particle abc in Maya

 

I guess AD is the guilty one here ... The good enough path is still to rely on Realflow bin ...

Share this post


Link to post
Share on other sites

I haven't been following this thread, but have you tried submitting an RFE for this? I'd submit an example particle abc from Maya 2016 so that they can know what Maya wants. This is assuming of course, that such an abc can also be successfully loaded back into Maya (test this).

Share this post


Link to post
Share on other sites

Still having the same issues to.
I had a workaround, adding the realflow plugin into Houdini  --> export the particles to a Realflow particle format --> Use the Realflow plugin for Maya, and Import the particles using the realflow  to maya plugin...

Edited by squardis

Share this post


Link to post
Share on other sites

@Edward

you are right iI could send a RFE but i'm afraid the problem is on the AD side.

their alembic translator doesn't handle particles imo.

 

the good workflow would be to mimic exactly the realflow way of doing things where you have

- an emitter link to an .abc cache

- a particle shape where you can still modify your particules after caching

Share this post


Link to post
Share on other sites

Havent tried exporting anything lately, but here are some thoughts. Have you guys tried putting dowm an add sop set to add particle system before exporting? This adds a particle system primitive to the Geo which might make ABC export correctly. It also may need a pimitivev group as well.

  • Like 1

Share this post


Link to post
Share on other sites

Exocortex is a very good solution but it is not free. I find that the realflow plugin which is free to download on Next Limit site a pretty convenient way of doing this.

This is especially true if you use maxwell for rendering.

 

For the plugin i can't reimport in maya a particle .abc done in maya. it works in H not in Maya, which tend to lead me to the conclusion that , AD hasn't done any proper workflow yet to use .abc to load particle cache.

 

But the point of ian is very valid, cause in fact at the begining i made the mistakes of exporting directly the point. the particle imported from maya are read as a particle system not only points so the add tricks will be valid when AD will release a proper reader.

Edited by sebkaine

Share this post


Link to post
Share on other sites

Have you tried Houdini Engine? In the simplest of cases, you could make an otl that is a file sop, or a locked node, or you can copy your base part of your working Houdini network into the otl. Once inside Maya you can just convert. 

 

As far as Houdini Engine integration with Maya. It does work pretty well off the shelf, and at least you can RFE any issues you run into and not have to worry about AD or other companies needing to support it. Though I am fan of the realflow plugin it's tried and true, but its like working with .obj for good and for worse.  

Share this post


Link to post
Share on other sites

I guess you're right Ben , maybe houdini engine is the most straightforward way ! but as the tool is extremely recent i was afraid it lakes stability for using it in production.

When deadline are very thin, i'm always careful with new tool, especially when they have to work inside Maya ... :)

Share this post


Link to post
Share on other sites

great news ! i didn't know that exocortex translator is now free

Share this post


Link to post
Share on other sites

Yeah we've been paralleling development of the exocortex with ABC and HoudiniEngine here. They both need a lot of love for large scale production work, I agree with you, but as a shuttle from Houdini to Maya they definitely work. The biggest problem is not with Houdini Engine or exocortex, it is the issue when Houdini throws an error, Maya just fucking crashes. Maya's biggest problem is it can't handle the full range of geometry types and workflows that Maya can handle. The install of Engine is easy, and in Maya the otl menu is pretty straight forward. Although you end up developing Maya specific tools, a.k.a. Maya sensitive so limit this option. 

 

But using HoudiniEngine just as a shuttle between the two programs that hasn't had any problems. 

  • Like 1

Share this post


Link to post
Share on other sites

alternatively Fabric Engine may be useful for bringing alembic to Maya and would possibly perform much better than anything else

and it's free for limited amount of licenses

 

but I definitely see this as Maya problem so maybe you'll have some luck banging on AD's door to fix their abc imoprter

Share this post


Link to post
Share on other sites

Thanks for precision guys , but for the moment i think i will stick with bin as i find quite elegant the way it link the cache to a maya particleShape than you can modify.

As we work mainly with Maxwell @work .bin has also the advantage of being natively support.

 

The fact that it works per frame is also an advantage in certain scenario compare to .abc

 

Like you confirm Ben, it's not that i am not trusting H Engine, but i have serious doubt for importing and playing with otl without bugs inside maya ... i'm maybe a pesimist, but i have bang my head on Maya Bug a Lot by the past ... :)

 

Fabric is also promising but still too fresh for the moment ...

Edited by sebkaine

Share this post


Link to post
Share on other sites

alternatively Fabric Engine may be useful for bringing alembic to Maya and would possibly perform much better than anything else

and it's free for limited amount of licenses

Houdini Engine is free with any license of Houdini, so if you are using Houdini you can use it in Maya.

Also Houdini Engine works off the shelf unlike Fabric Engine. You get nothing for free with Fabric Engine. I would not recommend the Fabric Engine approach it's an API, you need to write every piece from scratch. You need a dedicated python pipeline dev to support you for that.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×