Cryptomatte in Katana and Arnold /  by Xuan Prada

This post is mainly for my Patreon supporters. Some of them are having issues while setting up cryptomatte AOVs. This is how you do it.

  • Create a material node.

  • Add an AOVs shader -> cryptomatte.

  • If you are using the Arnold AOVs supertool, add all the cryptomatte AOVs that you need.

  • In the arnold global settings add the cryptomatte shader to the AOV shaders.

If you are not using the Arnold AOVs supertool.

  • Create an arnold output channel define node.

  • Set it to be crypto_material.

  • Type RGBA.

  • Add a render output define node.

  • Set the channel to crypto_material.

  • Repeat the same steps to create crypto_object and crypto_asset.

Katana Fastrack, episode 07 /  by Xuan Prada

Hello patrons,

Episode 07 of Katana Fastrack is already available.
In this episode we will work on the second and latest lighting shot of this course, a live action shot where we have to integrate some CG elements, in this case our very own Ant Man falling on the ground.

We will learn a few things like:

- How to quickly capture HDRIs on-set and lighting references.
- How to technical grade footage and HDRIs to live under the same context.
- How to approach live action shots in Katana.
- How to slap comp CG renders on top of a plate for validation.

More information on my Patron site.

Thank you very much for your support!
Xuan.

Wade Tillman - spec job /  by Xuan Prada

This is just a spec job for Wade Tillman’s character on HBO’s Watchmen. After watching the series I enjoyed the work done by Marz VFX on Tillman’s mask, that I wanted to do my own. Unfortunately, I don’t have much time so creating this asset seemed like something doable to do in a few hours over the weekend. It is just a simple test, it will require a lot more work to be a production-ready asset of course. I’m just playing here the role of a visual effects designer trying to come up with an idea of how to implement this mask into the VFX production pipeline.

I’m planning to do more work in the future with this asset, including mocap, cloth simulation, proper animated HDRI lighting, etc. I also changed the design that they did on the series. Instead of having the seams in the middle of the head from ear to ear I just place my seams in the middle of the face dividing the face in two. I believe the one they did for the real series works much better but I just wanted to try something different. I will definitely do another test mimicking the other design.

So far I just tried one design in two different stages. The mask covering the entire head and the mask pulled up to reveal the mouth and chin of the character, as seen many times in the series. I also tried a couple of looks, one more mirror-like with small imperfections in the reflections. And another one rougher. I believe they tried similar looks but in the end, the went with the one with more pristine reflections.

I think it would be interesting to see another test with different types of materials, introducing some iridescence would also be fun. I will try something else next time.

Capturing lighting and reflections to lit this asset properly has to be the most exciting part of this task. That is something that I haven’t done yet but I will try as soon as I can. It is pretty much like having a mirror ball in the shots. Capturing animated panoramic HDRIs is definitely the way to go or at least the more simple one. Let’s try it next time.

Finally, I did a couple of cloth simulation tests for both stages of the mask. Just playing a bit with vellum in Houdini.

References from the series.

Just trying different looks here for both stages of the mask.

Simple cloth simulation test. From t-pose to anim pose and walk cycle.

VES 2020 and LoSt in space breakdowns /  by Xuan Prada

We are back from our VES trip after a week in Los Angeles attending to the 2020 VES Awards Ceremony.
We were nominated for 4 VES Awards but unfortunately we couldn’t bring home any trophies this year.

ILP has published our 3 breakdowns for the categories that we were nominated. On top of these 3 we were also nominated for best VFX in episodic series. More Lost in Space breakdowns will be published in the near future.

Introduction to Reality Capture /  by Xuan Prada

In this 3 hour tutorial I go through my photogrammetry workflow using Reality Capture in conjunction with Maya, Zbrush Mari and UV Layout.

I will guide you through the entire process, from capturing footage on-set until asset completion. I will explain the most basic settings needed to process your images in Reality Capture, to create point clouds, high resolution meshes and placeholder textures.
Then I will continue to develop the asset in order to make it suitable for any visual effects production.

This are the topics included in this tutorial.

- Camera gear.
- Camera settings.
- Shooting patterns.
- Footage preparation.
- Photogrammetry software.
- Photogrammetry process in Reality Capture.
- Model clean up.
- Retopology.
- UV mapping.
- Texture re-projection, displacement and color maps.
- High resolution texturing in Mari.
- Render tests.

Check it out on my Patreon feed.

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.

Mari 4.6 new features and production template /  by Xuan Prada

Hello patrons,

I recorded a new video about the new features in Mari 4.6 released just a few weeks ago. I will also talk about some of the new features in the extension pack 5 and finally I will show you my production template that I've been using lately to do all the texturing and pre-lookDev on many assets for film and tv projects.

This is a big picture of the topics covered in this video. The video will be about 2.5 hours long, and it will be published on my Patreon site.

- Mari 4.6 new features
- New material system explained in depth
- Material ingestion tool
- Optimization settings
- How and where to use geo channels
- New camera projection tools
- Extension pack 5 new features (or my most used tools)
- Production template for texturing and pre-lookDev

All the information on my Patreon feed.

Thanks for your support!
Xuan.

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.

Introduction to Redshift for VFX - episode 03 /  by Xuan Prada

Episode 03 of Introduction to Redshift for VFX, is already available on my Patreon feedhttps://www.patreon.com/elephantvfx.
It is all about surfacing shading and the video is something around 4.5 hours.

These are the topics of this episode.

  • Camera mapping

  • Redshift uber shader

  • Sub surface scattering solutions

  • Texture management

  • UDIM workflow

  • Look-dev workflow

  • Surface shading

  • Look-dev tools

  • Normal maps, bumps and displacements

  • Zbrush and Mari displacements

  • Substance Painter workflow

  • Shading user attributes

  • Look-dev exercises

Check it out on my Patreon page.

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.

Katana Fastrack episode 05 /  by Xuan Prada

Episode 05 of Katana Fastrack is already published. In this episode we are going to take a look at the lighting pipeline that we could find in any visual effects studio.
First, I will explain quickly what is the most common workflow when starting a vfx production, from the lighting point of view.

Then, I will explain the recipe that we are going to cook in Katana for lighting shots. And finally, we will jump into Katana to build our lighting template, a tool that we are going to be able to use on many shots and sequences in the future.

Before finishing this episode, we will try our lighting template with very simple assets, testing features like importing look files, shading override, shading edits, geometry edits, etc.

All the info on my Patreon feed.

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.

Nuke IBL templates /  by Xuan Prada

Hello,

I just finished recording about 3 hours of content going through a couple of my Nuke IBL templates. The first one is all about cleaning up and artifacts removal. You know, how to get rid of chunky tripods, removing people from set and what not. I will explain to you a couple of ways of dealing with these issues, both in 2D and in 3D using the powerful Nuke's 3D system.

In the second template, I will guide you through the neutralization process, that includes both linearization and white balance. Some people knows this process as technical grading. A very important step that usually lighting supervisors or sequence supervisor deal with before starting to light any VFX shot.

Footage, scripts and other material will be available to you if you are supporting one of the tiers with downloadable material.

Thanks again for your support! and if you like my Patreon feed, please help me to spread the word, I would love to get at least 50 patrons, we are not that far away!

All the info on my Patreon feed.

Katana Fastrack episode 03 /  by Xuan Prada

Episode 03 of my Katana series is out. We are going to be talking about expressions, macros and tools to take our look-dev template to the next level. Right after that, we will take a look at the texture channels that I painted in Mari for this character and then we will start the look-dev of Ant-Man.

We divide the look-dev in different stages, the first on is blocking, and we are going to spend quite a few time working on this today.

All the info on my Patreon feed.

Introduction to Redshift for VFX, episode 01 /  by Xuan Prada

I'm starting a new training series for my Patreon feed, it's called "Intro to Redshift" for visual effects. I'm kind of learning Redshift and trying to figure out how to use it within my visual effects workflow, and I'll be sharing this trip with you. In this very first episode, I'll be talking about probably the most important topics around Redshift and the base for everything that will come later global illumination and sampling.

I will go deep about these two topics, sharing with you the basic theory behind global illumination and sampling, and I will also share with you a couple of "cheat sheets" to deal with noise and gi easily in Redshift while rendering your shots.

Check the first video out on my Patreon feed.

Cheers,
Xuan.