scene assembly

Solaris Katana interoperability part 2/2 /  by Xuan Prada

Hello patrons,

In this video we will finish this mini series about Solaris and Katana interoperability.
I'll be covering the topics that I didn't have time to cover in the first video, including.

- Manual set dressing from Solaris to Katana.
- Hero instancing from Solaris to Katana.
- background instancing and custom attributes from Solaris to Katana.
- Dummy crowds from Solaris to Katana.
- Everything using USD of course.

There are many more things that could be covered when it comes to Solaris and Katana interoperability, I'm pretty sure that I'll be covering some of them in future USD videos.

All the info on my Patreon.

Solaris Katana interoperability part 1/2 /  by Xuan Prada

Hello patrons,

This is small trailer for the video Houdini Solaris / Katana interoperability part 1/2.
The full video is published only for Patrons.
The whole thing is divided in two videos, the first one is around 2.5 hours and hopefully next month I can publish the second video covering the rest of the topics.

In this first video we are covering.

- Working template in Solaris.
- Working template in Katana.
- Full assets from Solaris to Katana.
- Modifying/overriding looks in Katana.
- Geometry assets from Solaris to Katana.
- Publishing looks as KLF.
- Publishing looks as USD files.
- Full assembly USD files.

All the information on my Patreon.

Thanks!
Xuan.

Houdini scatterers 2/2 /  by Xuan Prada

Hello patrons,

This is the second (and last) part of Houdini scatterers. We are going to take the tools that we made in the first video and see how we can use them to create complex and efficient scattering systems for your VFX shots, specially useful when dealing with huge environments.

I will show you some of my favourite worflows and share some techniques that I've used in the past in combination with the HDAs that we created in this series.

For those of you in tiers with downloadable material, you will have access to another post with some links to get the files.

As usual feel free to contact me with questions, suggestions, ideas, etc.
And if you like my content, please help me out and recommend it to you work mates.

All the info on my Patreon feed.

Thanks a lot for your suppor!
Xuan.

Simple spatial lighting /  by Xuan Prada

Hello patrons,

I'm about to release my new video "Simple spatial lighting". Here is a quick summary of everything we will be covering. The length of this video is about 3 hours.

- Differences between HDRIs and spatial lighting.
- Simple vs complex workflows for spatial lighting.
- Handling ACES in Nuke, Mari and Houdini.
- Dealing with spherical projections.
- Treating HDRIs and practical lights.
- Image based modelling.
- Baking textures in Arnold/Maya.
- Simple look-dev in Houdini/RenderMan.
- Spatial lighting setup in Houdini/RenderMan.
- Slap comp in Nuke.

Thanks,
Xuan.

Head over my Patreon site to access this video and many more.

Houdini scatterers, part 1/2 /  by Xuan Prada

Hello patrons,

This new video is part of the "little project" I made in Houdini and Redshift a while ago. In this part 1 of 2 video I show you how to create efficient tools in Houdini to deal with scattering, specifically focusing on environments. We are going to create a setup that takes care of randomization while using scattering techniques. Random rotation, random scale, random assets, etc.

Once the setups are done we are going to create tools or "digital assets" so you can re-use these tools as many times as you need in future porjects without re-doing the setups. We will create an interactive user interface to manipulate the tools.

In part 2 of this video I will show you different scattering techniques using these tools that we are going to build today.

The video is available on my Patreon site.

Thanks for your support!
Xuan.

Intro to LOPs and USD /  by Xuan Prada

My introduction to Houdini Solaris LOPs and USD is already available on my Patreon feed.
These are the topics that we are going to be covering.

- Introduction to USD and LOPs
- Asset creation worflow
- Simple assets
- Complex assets
- Manual layout and set dressing
- Using instances in LOPs
- Set dressing using information from Maya
- Using departments inputs/outputs
- Publishing system
- Setup for sequence lighting
- Random bits

This introduction is around 4.30 hours long.
Check it out here.

Introduction to Redshift - little project /  by Xuan Prada

My Patreon series “Introduction to Redshift for VFX” is coming to an end. We have already discussed in depth the most basics features like global illumination and sampling. I shared with you my own “cheat sheets” to deal with GI and sampling. We also talked about Redshift lighting tools, built-in atmospheric effects, and cameras. In the third episode we talked about camera mapping, surface shaders, texturing, displacement maps from Mari and Zbrush, how to ingest Substance Painter textures and did a few surfacing exercises.
This should give you a pretty good base to start your projects in Houdini and Redshift, or whatever 3D app you want to use with Redshift.

The next couple of videos about this series are going to be dedicated to doing from scratch to finish a little project using Redshift. We are going to be able to cover more features of the render engine and also discover more broad techniques that hopefully you will find interesting. Let me explain to you what is all of this about.

We’ll be doing this simple shot below from start to finish, it is quite simple and graphic I know, but to get there I’m going to explain to you many things that you are going to be using quite a lot in visual effects shots, more than we actually end up using in the shot.

We are going to start by having a quick introduction to SpeedTree Cinema 8 to see how to create procedural trees. We will create from scratch a few trees that later will be used in Houdini. Once we have all the models ready, we will see how to deal with SpeedTree textures to use them in Redshift in an ACES pipeline.

These trees will be used in Houdini to create re-usable assets llibraries and later converted to Redshift proxies for memory efficiency and scattering, also to be easily picked up by lighting artists when working on shots.

With all these trees we will take a look at how to create procedural scattering systems in Houdini using Redshift proxies. We will create multiple configurations depending on our needs. We are also going to learn how to ingest Quixel Megascans assets, again preparing them to work with ACES and creating an additional asset for our library. We will also re-use the scatterers made for trees to scatter rocks and pebbles.

To scatter all of that will be used as a base Houdini’s height fields. For this particular shot, we are going a very simple ground made with height fields and Megascans, but I’m going to give you a pretty comprehensive introduction to height fields, way more than what you see in the final shot.

Once all the natural assets are created, we’ll be looking at the textures and look-dev of the character. Yes, there is a character in the shot, you don’t see much but hey, this is what happens in VFX all the time. You spend months working on something barely noticeable. We will look into speed texturing and how to use Substance Painter with Redshift.

suit.png

Now that we are dealing with characters, what if I show you how to “guerrilla” deal with motion capture? So you can grab some random motion capture from any source and apply it to your characters. Look at the clip below, nothing better than a character moving to see if the look actually works.

It looks better when moving, doesn’t it? There is no cloth simulation btw, it is a Redshift course, we are not going that far! Not yet.

Any environment work, of course, needs some kind of volumetrics. They create nice lighting effects, give a sense of scale, look good and make terrible render times. We need to know how to deal with different types of volumetrics in Redshift, so I’m going to show you how to create a couple of different atmospherics using Houdini’s volumes. Quite simple but effective.

Finally, we will combine everything together in a shot. I will show you how to organize everything properly using bundles and smart bundles to configure your render passes. We will take a look at how Redshift deals with AOVs, render settings, etc. Finally, we will put everything together in Nuke to output a nice render.

Just to summarize, this is what I’m planning to show you while working on this little project. My guess is that it will take me a couple of sessions to deliver all this video training.

  • Speed Tree introduction and tree creation

  • ACES texture conversion

  • ACES introduction in Houdini and Redshift

  • Creation of tree assets library in Houdini

  • Megascans ingestion

  • Character texturing and look-dev

  • Guerrilla techniques to apply mocap

  • Introduction to Houdini’s height fields

  • Redshift proxies

  • Scattering systems in Houdini

  • Volume creation in Houdini for atmospherics

  • Scene assembly

  • Redshift render settings

  • Compositing

  • Something that I probably forgot

All of this and much more training will be published on my Patreon. Please consider supporting me.

Thanks,
Xuan.

Arnold interoperability /  by Xuan Prada

In this video I will guide you trough arnold operators in both Maya and Houdni to show you advanced methods for creating looks, and potentially anything arnold related. Working with arnold operators can be very beneficial in your visual effect pipeline, among other things you are going to be able to transfer "for free" pretty much anything from one 3D package to another, in this case from Maya to Houdini and vice-versa.

These days it is very common to work in a traditional 3D package like Maya while creating assets and then moving to a scene assembler like Houdini or Katana to do shots. With this workflow you are going to be able to do so in a very clean, tidy and efficient way.

On top of that, I'm going to show you how to create look files that can be easily exported to use in lighting shots, independently in Maya or Houdini. You also are going to be able to override looks, versioning looks in Shotgun and many more things.

This is a two plus hours video tutorial posted on my Patreon feed.

Thanks a lot for your support.
Xuan.

Creases from Maya to Houdini /  by Xuan Prada

This is a quick tip on how to take creases information from Maya to Houdini to be rendered with Arnold. If you are like me and you are using Houdini as scene assembler this is something that you will have to deal with sooner or later.

  • In Maya, I have a simple cube with creases, on the right side you can see how it looks once subdivided twice.

  • Not only you can take creases information into Houdini, you can also export subdivision information and HtoA will interpret it automatically. Make sure you add catclark subdivision type and 2 iterations, or whatever you need.

  • When exporting the alembic caches you need to include the arnold parameters that take care of subdivision and creases. Actually there is no extra parameter for creases, by including subdivision parameters you will already get the creases information.

  • Note that the arnold parameters in Maya start with ar_arnold_parameter, for example ar_subdiv_iterations. But in Houdini arnold parameters don’t use de ar prefix. Because of that make sure you are exporting the parameter without the ar prefix.

  • All this can be of course happen automatically in your pipeline while publishing assets. It actually should to make artists life easier and avoid mistakes.

  • That’s it, if you import the alembic cache in Houdini both creases and subdivisions should render as expected. This information can be overwritten in sops with arnold parameters.

Lighting a full CG shot in Houdini, part 02 /  by Xuan Prada

Hello patrons,

I just finished the second video for Lighting a full CG shot in Houdini, if you are a patron you will find it in the next private post. This is the content that we will go through in the video for almost three hours.

- Introduction to ACES in VFX. We will talk about the basics of ACES, why it's important for your productions, how to set it up in Houdini, Arnold and Nuke.

- CG lights. I will show you how we usually deal with CG lightings in relationship with principal photography. We will talk about the most common lights used while lighting a CG shot and the purpose of each of them. A very quick introduction to cinematography for VFX.

- Finally, we will jump into Houdini to create a master lighting template that you would be able to re-use in your shots. We will establish a tidy structure that will enable you to work straight away in Houdini. We will create smart bundles to setup automatically your render passes, and finally we will see how to use operators, probably the most powerful render feature ever!

Here the link to the episode.

Thanks for your support!
Xuan.

Render mask in HtoA /  by Xuan Prada

This is how to setup a render mask, or render patch, or whatever you want to call it, in Houdini using Arnold.
Render patches are generally used when a high cost render needs a fix that only affects to a small portion of the frame, or when most of the frame is going to be covered by a foreground plate.

In these scenarios there is no need to waste render time and render the whole frame, but just what is needed to finalize the shot.

  • This is the scene that I’m going to use for this example. Let’s pretend that we have already render 4k full range of this shot. All of the sudden we need to make some changes on the rubber toy screen left.

  • The best way to create a render mask is using Nuke. You can use an old render as template to make sure everything you need in the frame is covered by the mask. Rotopaint nodes are very useful specially if you need to animate your mask.

  • Create a camera shader and connect the render mask to its filter map.

  • Connect the shader to the camera shader input of the camera, in the Arnold tab.

  • If you render now, only the mask area will be rendered, saving us a lot of render time.

Huge limitation, that I don’t know how to fix and I’m hoping for someone to throw some light on this topic. If you are rendering with overscan, this won’t work nicely, let me show you why.

  • I’m rendering with a 120 pixels overscan, I know is generally speaking a lot, but I just want to illustrate this example very clearly.

  • Now if you render the same overscan with the render mask applied, you will get a black border around the render. Below is the render patch comped over the full frame render.

I’m pretty sure the issue is related to the wrap options of the render mask. By changing the wrapping mode you will get away of this issue in some shots, but in an example like the one on this post, there is no fix playing with the wrapping modes.

Any ideas?

You can definitely use the camera crop options and it will work perfectly fine, no issues at all. It is not as flexible as using your own textures, but it will do in most cases.

Katana Fastrack episode 06 /  by Xuan Prada

Episode 06 of "Katana Fastrack" is already available.

In this episode we will light the first of two shots that I've prepared for this series. A simple full CG shot that will guide you trough the lighting workflow in Katana using the lighting template that we created in the previous episode.

On top of that, we also cover the look-dev of the environment used in this shot.
We'll take a look at how to implement delivery requirements in our lighting template, such as specific resolutions based on production decisions.

We also will take a look and how to create and use interactive render filters, a very powerful feature in Katana. And finally, we will do the lighting and slapcomp of the first shot of this course.

All the info on my Patreon feed.

Lighting a full cg shot in Houdini, part 01 /  by Xuan Prada

Part 01 of "Lighting a full cg shot in Houdini" is out.

In this first episode I go through everything you need to convert Houdini into a powerful scene assembler, specially focused on look-dev. I will go through other assembly capabilities and lighting/render in future videos.

In this episode we will cover:

- How to organize and prepare assets in Maya to be used in Houdini for assembly and render
- Good uv workflows for vfx and animation productions
- How to assemble multiple assets in Houdini in a scene assembly fashion
- Quick look at speed texturing in Substance Painter
- How to create digital assets and presets in Houdini to re-use in your projects
- Look-dev workflow in Houdini and Arnold

All the information on my Patreon feed.

Thanks for your support,
Xuan.

Clarisse scatterers, part 01 /  by Xuan Prada

Hello patrons,

I just posted the first part of Clarisse scatterers, in this video I'll walk you through some of the point clouds and scatterers available in Clarisse. We will do three production exercises, very simple but hopefully you will understand the workflow to use these tools to create more complicated shots.

In the first exercise we'll be using the point array to create a simple but effective crowd of soldiers. Then we will use the point cloud particle system to generate the effect that you can see in the video attached to this post. A very common effect these days.
And finally we will use the point uv sampler to generate huge environments like forests or cities.

We will continue with more exercises in the second and last part of these scatterers series in Clarisse.

Check it out on my Patreon feed.

Thanks,
Xuan.

Katana Fastrack episode 04 /  by Xuan Prada

Katana Fastrack episode 04 is already available.
In this episode, we will finish the Ant-Man lookDev by tweaking all the shaders and texture maps created in Mari.

Then we will do a very quick slapcomp in Katana and Nuke to check that everything works as expected and looks good. We will do this by render a full motion range of Ant-Man walk cycle. And finally, we will write a Katana look file to be used by the lighters in their shots.

Check it out on my Patreon feed.

Patreon: Houdini as scene assembler: Bundles, takes and rops /  by Xuan Prada

In this video I talk about the usage of Houdini as scene assembler. This topic will be recurrent in future posts, as Houdini is becoming a very popular tool for look-dev, lighting, rendering and layout, among others.

In this case I go trhough bundles, takes and rops and how we use them while lighting shots in visual effects projects.

You will learn:

- Bundles, takes, rops
- Alembic import
- Different ways of assign materials
- Create look-dev collections
- Generate .ass files
- Create render layers
- Create quick slap comps
- Override materials

Check it out here.

Katana, constraint lights to an alembic geometry /  by Xuan Prada

One of the most common situations while lighting a shot is attaching a CG light in your scene assembler to an alemic cache exported from Maya. This is very simple to do in Katana, let’s have a look at it.
I’m using this simple animation of a car spining around.

01.gif

In most cases you need an object within the alembic cache that has the animation baked into it. The usual approach is to use a locator. To do so, snap it onto one of the lights geometry of the car and parent constrain it to the master control of the car. Then bake the animation of the locator and export it with the rest of the alembic cache to Katana.

In Katana, create a gafferThree node but do not place any lights yet. It is better to do the constraints first, if not you might have to deal with offset issues later on.
Use a parentChildConstraint node indicating the gaffer node in the basePath and the locator of the car in the target.

Now place both headlights according with the model of the car. If you press play they should follow the animation of the car perfectly.

04.gif

In case you forget to do the parentConstraint before adding lights to the gaffer, you might have to control the offset and compensate for it. To actually see the values you can add constraintResolve and a transformEdit to check the transformations.