Welcome to od|forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.

Steve Cullum

Houdini to Lightwave pipeline?

22 posts in this topic

Hi,

I'm new to this forum, but everyone is saying this is THE Houdini place on the web :). So I'm hoping some of you guys can help me out.

I'm trying to work out a pipeline for exporting Houdini animation and fluid based effects to LW for rendering. eetu has kindly posted up an mdd reader/writer which should take care of any animations without point number changes, but I'm still having problems with fluid type stuff.

I can export .obj as a sequence, but the real challenge is batch converting to lwo format and surfacing them. I've now got hold of the old next-limit plugin for replacing surfaces, but I still need a way to batch convert obj's to lwo's.

Ideally it would be good to write directly to the LWO format from Houdini, but I can't seem to do that.

If anyone has any suggestions its appreciated!

Share this post


Link to post
Share on other sites

Hi!

This is something I've been trying to work on a little bit every now and then, no beautiful solution yet.

The options I can see at the moment:

- Use realflow .sd format, you don't need realflow itself, export from H, import to LW.

- Save .obj sequence from H, load as object sequence to LW, export to .lwo sequence with "Save Transformed Sequence" (http://www.interialabs.de/lw/lscript/). Surface using the old realflow surfrep.exe

- Save .geo sequence from H, load as object sequence to LW (using my .geo loader http://undo.fi/houdini/lw-geo/). Otherwise as above. This is more fragile but allows you to transfer houdini attributes.

- I haven't tried FBX, but perhaps worth a try?

Awkward, yes. Doable, yes :)

Share this post


Link to post
Share on other sites

Hi Steve. Nice to see another LW

Edited by Netvudu

Share this post


Link to post
Share on other sites

I'm pleased to be among friends ;)

Which version of Lightwave are you using the batch edit script with? - I keep getting an error line 268 invlaid object method in 9.3.1

I'll give the save script a try and see if that will work. It would be nice to have a plugin that can save out lwo format directly though!

Thanks!

Share this post


Link to post
Share on other sites

If you're feeling ambitious, there's a Blender python script for exporting object sequences to .lwo. It shouldn't be too difficult to convert it to Houdini (which uses Python as well.) You could then convert your surfaces right inside the script.

And if you're feeling really ambitious, there's a section in the Houdini help describing how to write your own custom importer.

You might find it useful to know that Houdini exports its groups in .obj files, which are read into LW as parts. So, by using the Parts -> Surfaces command, you can transfer your Houdini group names to LW surface names.

By the way, LW will not create motion blur on an object sequence (unless something's changed recently.)

Share this post


Link to post
Share on other sites
If you're feeling ambitious, there's a Blender python script for exporting object sequences to .lwo. It shouldn't be too difficult to convert it to Houdini (which uses Python as well.) You could then convert your surfaces right inside the script.

And if you're feeling really ambitious, there's a section in the Houdini help describing how to write your own custom importer.

You might find it useful to know that Houdini exports its groups in .obj files, which are read into LW as parts. So, by using the Parts -> Surfaces command, you can transfer your Houdini group names to LW surface names.

By the way, LW will not create motion blur on an object sequence (unless something's changed recently.)

Yeah I had a look at that script - but I would have to feeling very ambitous indeed! - I hardly know my way round an expression right now (always avoided in LW) :unsure:

I got the objsequence to .lwo working which is a major step forward. I've also got an external app from next limit that will replace the surfaces on a sequence of lwo's, so I'm almost there!

I know MB is an issue, but reelsmart does a great impression of the real thing - even without vectors!

Share this post


Link to post
Share on other sites
If you're feeling ambitious, there's a Blender python script for exporting object sequences to .lwo. It shouldn't be too difficult to convert it to Houdini (which uses Python as well.) You could then convert your surfaces right inside the script.

Ah, gotta take a look, thanks for the tip

By the way, LW will not create motion blur on an object sequence (unless something's changed recently.)

That was perhaps the main reason for my .geo importer, I wanted to do just that:

- calculate v in Houdini and export .geo sequence

- import geo into LW, add "Object sequence" replacement plugin

- add morph mixer to the object, there should be a "v" morph available

- enable fractional keyframes in the options

- add a -100% morph keyframe at -0.5 frames and a +100% key at 0.5 frames, set loop behaviour to repeat.

Might be a good idea to combine with the previous and convert to .lwo sequence first.

eetu.

Share this post


Link to post
Share on other sites

What you're describing is, I believe, how RealFlow works in LW. I once tried doing that with Blender, but I couldn't get consistent velocity vectors from Blender when the point count difference was significant. But I did update that Python script so that it would create the velocity endomorph.

If you'd like, I'll post my modification here -- that should take you a little closer.

Share this post


Link to post
Share on other sites

mmm....Realflow does work this way and those endomorphs are based on the velocity, so if the endomorphs created by eetu were based on the "v" attribute I don

Edited by Netvudu

Share this post


Link to post
Share on other sites

Blender creates a velocity file that's used by its vector blur compositing node. The file's not documented, so I had to backward engineer it from the C code (and possibly not %100 correctly.) When the point counts were consistent from frame-to-frame, it worked -- but if the mesh got more dense, the points that didn't exist in the previous frame would have nonsensical velocities.

Share this post


Link to post
Share on other sites

What about FBX? It should work without many probs.

I did a LW to Houdini exporter a few years ago, but at some unknown Houdini update it got broken and I haven´t fixed it because FBX tends to work.

Share this post


Link to post
Share on other sites

 

hi eetu,

 

is there any chance to get the .geo importer as a LightWave 64bit version, i believe it is 32bit now... ?

Share this post


Link to post
Share on other sites

If you could share the source code I would try to build a x64 version. 

 

best martin

Share this post


Link to post
Share on other sites

I can't find the source at the moment, sorry. I do have an archive which is not online, I'll dig it up and check, it should be somewhere :)

Share this post


Link to post
Share on other sites

 

hi eetu,

 

is there any chance to get the .geo importer as a LightWave 64bit version, i believe it is 32bit now... ?

+1 for the 64bit LW version if it's not much of a hassle. Thank you in advance eetu! :)

Share this post


Link to post
Share on other sites

Against all odds I actually did find it when looking through an old usb HD!

I downloaded a trial of LW2015.3 64bit, and this seems to work.

It is very finicky, seems to only load the very basic geometry, points and polygons and nothing else.

Also, it needs to be saved as .hclassic

I have to say it has been a few years... :)

edit: Actually, it does load point attributes as documented in the original download page http://undo.fi/houdini/lw-geo/

Just make sure there are no vertex/primitive/detail attributes there to throw it off..

ee_hougeoimport64.zip

Edited by eetu

Share this post


Link to post
Share on other sites

very-very cool !  smile.gif

 


 

It is very finicky, seems to only load the very basic geometry, points and polygons and nothing else.

 

did the 32bit version also have this issue, only did some small tests, but seemed fine. but could be it also had it.

 

other coders might, maybe, be able to solve the geometry limit problem,

if you found the source files that would be awesome (!)

 

047.gif

 

 

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