Category: Advanced & Experimental

Here’s a look at the final product of the artwork and below is the VFX Breakdown.

For the adjustment of the shadows, I redid all the blood in NUKE, then I divided the original video into three layers and added them in order to the main Pipeline, of course the two layers of the shadows were using the same parameters and acted on two blur nodes

I then added a Roto channel to each of the shadow layers to make them both appear only on the left side and the right side.

In the landscape frame, I noticed that the camera shake was now disengaging the EXR sequence of the blood, and a portion of the blood video was currently inside the frame, so I added a 2D tracking to it to match the camera shake

More Process please scroll down ^ ^

This post chronicles the progress of my personal project this week, featuring the addition of new VFX lenses.

First of all, I am going to add some effect of blood being splattered on the wall in the shot of blood pouring into the tunnel, I first used a MOV format, but it didn’t work as well as it should have, because my shot was created by simulation of mono-water, so the direct compositing would have been very fake in the scene, and if I had this shot composited by pure CGI, or HOUDINI plus MAY or UE5, it would have been possible to achieve a very good effect

So I was going to try a new approach to this problem next week, and then I created a second FX shot, this one a horizontal one showing the blood rapidly catching up with the protagonist. So I was going to try a new approach to this problem next week, and then I created a second FX shot, this one a horizontal one showing the blood rapidly catching up with the main character. The difficult part in this shot was adjusting the size of the blood motion blur in proportion to the speed at which the blood was moving, and eventually I found a good state of affairs.

Then I started to FX the last shot, I was going to create a first person view of blood, firstly I mediated the lens in HOUDINI

Then to handle the high speed movement of the camera I did 3D tracking of the shot in NUKE, while tracking I used roto to remove the figure to keep the GPU from tracking the figure thus producing a completely wrong point cloud.

Then I speeded up that video in Ae, because the final section of the video where the water is supposed to go down due to gravity and thus become faster, but the original video was at a constant speed

I’ve continued to import more accurate camera data into Houdini.

Checking the rendered result

Here’s the original video, you can see that there are five main light sources in the frame, which I then added to Houdini’s tunnel scene

Here the project files are all ready, I have increased the accuracy of the blood simulation by a factor of 10 here, and you can see that the result is now very much like the real scene (the simulation cache is also very large)

This is the particle effect of the model just now, you can find that the particles are super, just look at the effect of the particles is already perfect!

This is what the rendering looks like at this point!

Then I started the rendering and imported the result into NUKE, where I tracked the light source of the original video in 2D and transferred the data to the blood video

Then I added a Lightwrap attribute, a node that allows the high brightness of the edges of the blood to blend more with the original tunnel video. I then used a trick taught by Gonzalo to check exposure as well as saturated frames to check if the blood video was too bright? Or is it too saturated? If so, go ahead and add a Grade or ColourCorrect node to adjust it.

I ended up rendering the NUKE and editing the video in Pr

Here are the results of my video this time

In terms of fluid detail, I continued to tweak the emissive source density, fluid viscosity, and surface tension of the water body; I still don’t actually have specific tunneling parameters at this point, but the tweaks to these nodes are permanent, and I can import them directly for use in a new model.

After I learnt about the KARMA renderer, I did an initial render of the scene, I added a darker EXR sky file to the background to for the dimness of the tunnel. Then I thought the result was still good at this point! But I realised later that I was too happy too soon, and every time I solved one problem, two new ones popped up!

What comes next is the most important thing, imagine if you had to blend a Houdini render with a formal scene?

1: Use the Karma renderer to render the parts of the body of water and mask out the tunnels, as it’s very cumbersome and ineffective to deal with in NUKE.
2: Export the water as a separate ABC file then import it into Maya for rendering
3: Direct rendering, not shooting the real scene later, using green screen to shoot the characters and composite them into the CG scene.

After thinking about it and trying it out, the only possible ways to handle it were 1 and 3, but at this point I had already finished drawing the storyboards as well as preparing for the shoot, so I ruled 3 out.
But there is a big problem in option 1, if I exclude the wall of the tunnel from the rendering, with the same time I have to not show the water behind the wall?

The most likely solution I tried was to split the water (blood), the wall and the emission source into three different Geo’s with different render numbers for them, but it still failed!

Then I asked Alwin (so reliable!) , he didn’t know either at first, but he started out by saying that Houdini’s default Mantra renderer could separate the two layers and render them very quickly, which I found out it could be done, but by this time I had already prepared the render in Karma and Alwin was happy to help, so he called to a friend of his from a VFX company and he finally found a solution with it! (It’s really hard to solve, you can’t even find examples in the official answer site)

Here’s what it looks like when it’s all settled, it’s so convenient! And you only need to add one node and write a command!

Here are the solutions

I also completed all the shoots this time and here are some images from the shoot. And since I needed to make a model of the tunnel exactly like the scene, I shot an extra video for 3D tracking.

This video below is my initial edited work, and it’s already just under a minute long

The name of this project is Blood Flood, a short public service film, or advert, about drug rehabilitation. At the beginning when I decided on the theme, I was going to create 4 short stories to express the theme, but Klaus said it would be too long and the audience wouldn’t know the point you are trying to make, so I shortened the story to one clip, here is the storyboard of my initial design.

Since I’m going to create this project through Houdini’s fluids, I’ve collected a lot of related tutorials as well as effect videos. My favourite is the following one

In terms of workflow, I still use Figma for integration, including my mind map, part of my workflow, and some reference images. And this time I will also record some of the difficulties I encountered in the project in Figma, so that my work will be completely based on this software, which will have a great effect on the speed of work!

Here are some reference images I found in the pre-production for the visual effects

Those four images are the most important reference images for me when I create a body of water in the later stages of the process

In making it, I first tested the particle simulation using the nodes on the Houdini tool rack, and added some 3D model to test the buoyancy (although it wasn’t used later)

Next, after testing, I attempted to make a 3D model of the tunnel myself (at this point I hadn’t decided on the details of the shot, so I made a small tunnel to test the fluid first)

Next, I imported the model into Houdini and added it as a collision body and converted it to a smaller model (which makes the calculations faster), then I added the emission source at the end of the tunnel

After updating my tunnel model the water flowed properly, I omitted a lot of parameters on this side, in fact I spent a lot of time on tweaking them, all parameters need to be adjusted one by one. For example, the particle emission density and the gravity (if gravity is not added to the x-axis, it is difficult for the water to flow from the back into the tunnel).