EDIT: I wrote this before Gametools was rebranded as SideFX Labs….

I have just a basic observation from someone who is very much an artist with almost zero TD skills and has minimal game knowledge; so take everything with that in mind.

At nearly age 50 I'm back in grad school pursuing my MFA in motion media design. I'm currently taking an elective in creating environments with UE4. Obviously, I wanted to leverage Houdini Engine for the class and I've been trying. But what I run into time after time is, the tools are updated so quickly and with so little documentation or tutorials, I routinely find myself watching a presentation from 1-3 years ago, only to find out that workflow isn't how things are done, but instead there's a new node, new tool, etc., etc.

It makes it really frustrating for a student who doesn't really know UE4 and has no experience with Houdini Engine. You see video after video explaining how something is now incredibly easy and simple, but it's out of date or not really documented for newbs like myself.

Could someone just be in charge of general housekeeping? So if a tool is out of date or significantly updated, perhaps pull down the old videos or at least mark them with a note that a newer technique or tool now exists with a link to that tool/technique?

I also have noticed most of the documentation, tutorials and videos tend to skip large chunks of information on either the Unreal side or the Houdini side, assuming the viewer already knows whatever is being discussed. So I can create a simple HDA and bring it into UE4, but there doesn't seem to be any information on how to UV/texture/surface something like that either in Houdini first or in UE4 after import.

At the moment I am doing what should be very simple. I want to use the built-in Steam PyroFX to create some whispy smoke in my UE4 environment. I've found multiple, semi-incomplete tutorials from SideFX and others on similar topics, but none of them really explain when or why you'd use a particular technique or if the technique is still valid.

Example 1: https://vimeo.com/207832662 [vimeo.com] Vertex Animation GDC Project - looks like it'd deal with smoke, but it's not really particles or a fog-like volume. I tried following along, but the tools are different and even when I thought I'd managed to nail it, my imported mesh wound up a jumbled mesh (even with the correct UV settings in UE4).

Example 2: https://vimeo.com/265077965 [vimeo.com] - Fire Presets Game Tools - not exactly what I was looking for, but interesting. However, there's zero information on how to take them from Houdini and get them to Unreal. If it's a game tool, it'd be nice to know how to get things into a game engine.

Example 3: https://www.sidefx.com/tutorials/channel-packing-pyro-data-using-the-texture-sheets-rop/ [www.sidefx.com] - Game Tools PyroFX Texure Sheets. Looks amazing. But I have no idea how to go from Houdini to UE4. He shows Unreal. He shows how excellent things work. He just skips any information on how to actually use any of it. I have no idea what a texture sheet is. Is it something native to Unreal? It's not been covered in my class. I downloaded the example files - they're all .ueassets - great, but not really helpful in going from Houdini to UE4.

Finally: https://www.sidefx.com/docs/unreal/index.html [www.sidefx.com] - the docs. Can you find any examples of how to use anything? How about, right after the info on installation, something simple like, “lets create a textured cube HDA that can have some parameters changed in Unreal”? Or, here's the basic workflow for making an HDA in Houdini that ends with a finished, game-ready, textured, surfaced asset? There doesn't seem to be anything in the docs that helps get the new user up and running.

The docs are just not “artist friendly”. I didn't want to be hit with RTFM, but if anyone can point to the docs and show how I can take a basic PyroFX steam object from Houdini and get it into UE4, I'd be thrilled.

Sorry for the long rant, but it is really frustrating when you absolutely know things are possible and shouldn't be as difficult as they seem. I just spent over an hour rendering with the Texture Sheets ROP only to discover there doesn't seem to be any information on what to do with what you get from the node over to Unreal.

-Paul

Hey Paul,

Thank you for taking the time to write such a detailed post. You've clearly done your very best to figure this out on your own but still left feeling very frustrated. I'm going to try 2 routes to help you out.

First. If you can, I'd recommend you check out Andreas Glad's, Houdini VFX for Games. [www.pluralsight.com] He does a great job of laying out the full process from beginning to end. Setting up a simulation, rendering that out to a texture sheet. Setting up your particles system and material in UE4.

The other option is to try and piece together what you already have. I think you've found all the right pieces. We just need to string them together.
1. The fire presets node is an easy way to create a simulation without having to worry about too many settings or dive into DOPs. But if you want to do smoke and you're willing to spend a bit more time understanding fluid simulations you could start with this tutorial, https://www.youtube.com/watch?v=r_WErTEvAic [www.youtube.com]

2. Once you have your basic simulation we need to render that out to a texture sheet. This is where the texture sheet node comes into play. It will render out a sequence of images and then combine that into a single image. Most game engines don't support volume data natively so we render it out to a texture and then fake the volumetric look in the game engine.

3. Once you've imported your texture into UE4 you need to hook that up in a material. SubUV Textures are pretty common in UE4. You can learn more about them here. https://wiki.unrealengine.com/SubUV_Particle_(Tutorial)

At this point, you should have the basics of what you need.

You mention bringing HDA's into UE4 a couple of times which is a separate topic in itself. I'd suggest starting with Rob Magee's video from a couple of years back on getting started with Houdini Engine. It's a couple of years old but still relevant.

Mike