Vector displacement in Modo /  by Xuan Prada

Another quick entry with my tips&tricks for Modo.
This time I’m going to write about setting up Mudbox’s vector displacements in Modo.

  • Check your displacement in Mudbox and clean your layer stack as much as you can. This will make faster the extraction process.
  • The extraction process is very simple. Just select your low and high resolution meshes.
  • Set the vector space to Absolute if you asset is a static element, like props or environments.
  • Set the vector space to Relative if your asset will be deformed. Like characters.
  • Always use 32 bit images.
  • As I said export the maps using EXR 32 bits.
  • Before moving to Modo or any other 3D package, check your maps in Nuke.
  • Once in Modo, select your asset and go to the geometry options.
  • Check Linear UVs and set the render subdivision level.
  • Assign a new shader to your asset.
  • Add a new texture layer with your vector displacement map.
  • Set it up ass Displacement Effect.
  • Set the low and high value to 0 and 100.
  • You will see a displacement preview in viewport.
  • Set the gamma to 1.0 Remember that 32bit images shouldn’t be gamma corrected using Linear Workflow.
  • In the shader options set the Displacement Distance to 1m this should give you the same result than Mudbox.
  • In the render options you can control the displacement rate, which is your displacement quality more or less.
  • 1.0 is fine, play with that. Lower values will give you sharper results but will need more time to render.
  • Finally render a quick test to see if everything looks as expected.

Zbrush displacement in Modo /  by Xuan Prada

Another of those steps that I need to do when I’m working on any kind of vfx project and I consider “a must”.
This is how I set up my Zbrush displacements in Modo.

  • Once you have finished your sculpting work in Zbrush, with all the layers activated go to the lowest subdivision level.
  • Go to the morph target panel, click on StoreMT and import your base geometry. Omit this step if you started your model in Zbrush.
  • Once the morph targer is created, you will se it in viewport. Go back to your sculpted mesh by clicking on the switch button.
  • Export all the displacement maps using the multi map exporter. I would recommend you to use always 32bit maps.
  • Check my settings to export the maps. The most important parameters are scale and intensity. Scale should be 1 and intensity will be calculated automatically.
  • Check the maps in Nuke and use the roto paint tool to fix small issues.
  • Once in Modo, import your original asset. Select your asset in the item list and check linear uvs and set the amount of subdivisions that you want to use.
  • Assign a new shader to your asset, add the displacement texture as texture layer and set the effect as displacement.
  • Low value and high value should be set to 0 and 100.
  • In the gamma texture options, set the value to 1.0
  • We are working in a linear workflow, which means that scalar textures don’t need to be gamma corrected.
  • In the shader options, go to the surface normal options and use 1m as value for the displacement distance. If you are using 32bit displacements this value should be the standard.
  • Finally in the render options, play with the displacement rate to increase the quality of your displacement maps.
  • 0.5 to 1 are welcome. Lower values are great but take more time to render, so be careful.
  • Render a displacement checker to see if everything works fine.

Lego /  by Xuan Prada

I continue with my transition to Modo. I already know more or less the basics of the software and I have adapted my way of working to be productive in Modo. It’s time to make my first image and put in practice all that I learnt last week.

I have chosen a simple theme. After watching The Lego Movie (and some great references that they used) I wanted to create something related with it. It’s simple enough to allow me to finish the image in half a day or so. Say hello to all my mates who worked on the movie, we worked together on Happy Feet while ago.

The model for the character is quite simple, perfect to try all the modeling tools that come with Modo. Great so far. The work plane is quite useful, love it.

Modo’s uv mapping tools are great and very fast. I love atlas projection and unwrap. I’ll be using them all the time. For this particular model I used only unwrap. Just select a few edgest and that’s it, done. I didn’t worry much about seams, I can fix that later in Mari.
I’m using only one UDIM, this model and textures are simple enough to use only un uv space.

I worked on the textures in Mari. I could have used Modo paint tools, but I’m used to paint in Mari, and it’s definitely faster and more powerful.

Only needed three texture channels. Color, Specular and Bump maps. I used two different bump maps, one with fine noise for the plastic, and another one with scratches and imperfections.
All the textures are 8k resolution sRGB and Scalar and 16bit .tiff

For the look-dev I created an Image Based Lighting rig. With an overcast HDRI, perfect to create atmospheric lighting without too much direct light coming from the sun. It gives me perfect reflections and nice contrast between light and shade.
Always working with a Linear Workflow.

Only used one single shader, with no layers. Simple shader with a bit of reflection driven by a specular map.

For the ground I used a simple grid sculpted in Zbrush. Just a few dunes and procedural noise to simulate sand.

I did a few tests to find the best way to setup Zbrush displacements in Modo.
I’ll be posting soon how to do it. It’s not that complicated :)

For lensing, I used a 50mm focal length camera. I created a low poly version of my characters and ground, just to block the camera angle and lighting.

Finally, I updated the proxy models with the final ones.
To lit the scene I used a nice high resolution panorama shot by myself. It gave me the perfect atmosphere and reflection for this shot. But I couldn’t get the perfect shadows.
I wanted to lit this like a miniature, so I wanted a very strong key light with a perfect and hard shadow. I just removed the sun from the HDRI and then added a 3D light just behind the characters.

I dind’t need to render aov’s or render passes, I just rendered a quick id matte to control the ground and the characters.

This is the final render.

And finally, the black and white image that I conceived from the very beginning.

Multi UDIM workflow in Modo /  by Xuan Prada

You know I’m migrating to Modo.
Multi UDIM workflow is on my daily basis tasks, so this is how I do the setup.

  • First of all, check textures and UDIMs in Mari and export all the textures.
  • Check the asset and UVs in Modo.
  • Load all your textures in the Modo’s image manager.
  • Create a new material for the asset.
  • Add all the UDIM textures as image layers for each required channel.
  • In the texture locator for each texture change the horizontal repeat and vertical repeat to reset. And change the UV offset. It works with negative values (not like Softimage or Maya).
  • That’s it. Make a render check to see if everything works fine.

MeshLab /  by Xuan Prada

Just pointing up to a great tool that I’ve been using lately.
It’s a fast, stable and free .obj viewer for Mac, I’m using it a lot while scanning on set, just works great! give it a try.
All the information here http://meshlab.sourceforge.net/

And a couple of screenshots.

Fixing “nadir” in Nuke /  by Xuan Prada

Sometimes you may need to fix the nadir of the HDRI panoramas used for lighting and look-development.
It’s very common that your tripod is placed on the ground of your pictures, specially if you use a Nodal Ninja panoramic head or similar. You know, one of those pano heads that you need to shoot images for zenit and nadir.

I usually do this task in another specific tools for VFX panoramas like PtGui, but if you dont’ have PtGui the easiest way to handle this is in Nuke.
It is also very common when you work on a big VFX facility, that other people work on the stitching process of the HDRI panoramas. If they are in a hurry they might stitch the panorama and deliver it for lighting forgetting to fix small (or big) imperfections.
In that case, I’m pretty sure that you as lighting or look-dev artist will not have PtGui installed on your machine, so Nuke will be your best friend to fix those imperfections.

This is an example that I took while ago.One of the brackets for one of the angles. As you can see I’m shooting remote with my laptop but it’s covering a big chunk of the ground.

When the panorama was stitched, the laptop became a problem. This panorama is just a preview, sorry for the low image quality.
Fixing this in an aquirectangular panorama would be a bit tricky, even worse if you are using a Nodal Ninja type pano head.
So, find below how to fix it in Nuke. I’m using a high resolution panorama that you can download for free at akromatic.com

  • First of all, import your equirectangular panorama in Nuke and use your desired colour space.
  • Use a spherical transform node to see the panorama as a mirror ball.
  • Change the input type to “Lat Long map” and the output type to “Mirror Ball“.
  • In this image you can see how your panorama will look in the 3D software. If you think that something is not looking good in the “nadir” just get rid of it before rendering.
  • Use another spherical transform node but in this case change the output type to “Cube” and change the rx to -90 so we can see the bottom side of the cube.
  • Using a roto paint node we can fix whatever you need/want to fix.
  • Take another spherical transform node, change the input type to “Cube” and the output type to “Lat Long map“.
  • You will notice 5 different inputs now.
  • I’m using constant colours to see which input corresponds to each specific part of the panorama.
  • The nadir should be connected to the input -Y
  • The output format for this node should be the resolution of the final panorama.
  • I replace each constant colour by black colours.
  • Each black colour should have also alpha channel.
  • This is what you get. The nadir that you fixed as a flat image is now projected all the way along on the final panorama.
  • Check the alpha channel of the result.
  • Use a merge node to blend the original panorama with the new nadir.
  • That’s it, use another spherical transform node with the output type set to Mirror Ball to see how the panorama looks like now. As you can see we got rid of the distortions on the ground.

P-maps /  by Xuan Prada

P-maps or position maps are one of those render passes that can save your life sometimes. They are really useful for compositing artist, matte painters or texture artists. You can save a lot of time rendering p-maps out from your rendering engine and avoid those tiny changes in a 3D software to rely on 2D or 2.5D techniques.

I personally use p-maps for different purposes, let me tell you some of them.

To place cards or another 2,5D or 3D elements

  • This is the render that I’m using for this small article. Nothing fancy there, just a few cubes and a couple of direct lights. This image has been rendered in Maya and V-Ray but of course you can render p-maps with any other combination of 3D program and render engine.
  • As additional render passes for this image I got the “normal pass” and the “world position pass”. You probably know that there are three different p-maps: World position, camera position and object position. They can be used for different purposes but all of them have the same kind of information, which is position.

    As they name says, one is the position information based on the world centre, the second one has the position in relationship with the camera, and the third one the position based on the centre of the object.

    You can render out all of them if you need, but for this example I’m going to use only world position map. All the techniques shown here can be extrapolated to the other maps.
  • This image is an .exr with all the render passes embedded so you can easily switch between them.
  • This is how the world position map looks like.
  • And this is how the normals pass looks like.
  • Use a shuffle node to read the p-map. If you need to un-premultiply it you can do it before the shuffle.
  • Use a position to points node to read the p-map and convert it to a 3D view.
  • Now you can move around the scene like any 3D software. This is extremely useful if you need to place any 2,5D or 3D element, like cards for example. Cards are extremely useful to place matte paintings, animated 2D elements, etc. You don’t need to guess anymore, just place your card in the right position.

To re-lit completely your scene

  • This is how your scene looks like out from the render package.
  • As we did before shuffle the p-map.
  • Take a re-light node. Connect the rgb to the color and the shuffle to the material. Then tweak the re-light node and select the normals and the point position.
  • Finally create a camera node and a scene node. Hook them all to the re-light node.
  • Now create a light node and connect it to the scene node. Play with the light to re-lit your scene.
  • As we see before, you can use your 3D scene to place the light.

To add subtle lighting information (or not that subtle)

  • Use a p-matte node to input your p-map and to output the information to the alpha channel. If you play with the shape, position and scale you will see the information of your new light in the alpha channel.
  • Connect the p_matte to the mask input of a grade node and play with it to tweak the intensity and color of the light.
  • Use a plus node to add as many lights as you need.
  • Of course you can help yourself to place the lights using the 3D view provided by the p-maps.

To project through camera

  • Projecting mattes, smoke, or any other information has never been so easy. Use the 3D view and a 3D camera to project detail on to the current render.
  • You can create a new camera or import it from your 3D package.
  • Use a re-project node to connect the camera, the image that you want to project (in this case a grid) and use a shuffle node with the p-map to provide vector information.
  • Finally I’m using a merge node to combine the grid projection with the original render and it’s being masked out using the embedded alpha from the .exr render.
  • Of course you can use the 3D view to place or modify the camera.

Shooting gear for VFX photography /  by Xuan Prada

This is the gear and setup that I’ve using lately for my shootings.
I’ve been shooting in Northern Spain for a few days surrounded by amazing places.

This two images were taken with my iPhone and you can show here all my HDRI for VFX gear to be used “on the go”. The panoramas for this location will be posted on akromatic.com soon.

For now, you can check another panorama taken that same day with the same gear.
Find it below.

More information at akromatic.com

Digital Colour Checkers /  by Xuan Prada

Just in case you forget your real colour checkers, you can download these ones and use them on your iPad mini, iPad air or iPhone.
They don’t replace the original ones but at least, you won’t be completely lost on set.

The only thing you have to do is download the following images and open them in your device.
I recommend using 100% of brightness.

Colour checker for iPad mini.

White Balance checker for iPad mini.

Colour checker for iPad air.

White Balance checker for iPad air.

Colour and White Balance checker for iPhone.