David Miranda Dev Blog

Foliage lighting model

2012-02-08T17:26:00.000-08:00

New / still un development lighting model for thin surfaces such as leaves.

Glass

2012-01-16T12:20:00.000-08:00

Ive been looking for a method to simulate a screen space distortion based on the mesh shape. For now, the most common method is DistortedScreenUV=ScreenUV+NormalMap x DistortionFactor. But, what normals to use? World Space normals? Maybe yes, but good luck getting them in UDK. So my trick here to solve this problem is using a spherical world normals texture and using spherical mapping. Hmm, is it correct? Of course not, but what's correct in game rendering? The cheaper!!

In combination with the translucent shader:

The trick behind:

Later, I wanted to test a real refraction. That one you cant ever use in a game, because its refracting a cubemap. On the left, void figure, on the right, solid:

Diffuse Convolution

2011-12-28T14:09:00.000-08:00

Ambient light in UDK comes from 3 possible sources:

SkyLight
Spherical Harmonics
Lightmaps

Another way for static models is to use Diffuse Convoluted cubemaps. It helps to integrate our model with our scene color. For me this is the best solution to fake GI without baking light. Its a fast and 'easy' process and correct color is ensured. Perfect for model showoff.

As first example, I just made a Phong+Lambert*DiffuseConvolution:

At first, I had a problem, because UDK rotates cubemaps -90 in X axis. So I had to do some matrix rotation in the pixel shader to find what was wrong there.

Rotation in X=90 was my first attempt, so it was fast. Once I known that, I had to find a software to do this. HDR Shop was the solution.

The next step was made in CubeMapGen. I imported the hdr file created in HDR Shop and applied the needed filters. Then, export CubeMap as images and we are done, ready to import to UDK.
I used public Light Probes, just for now, for testing. But the idea is to export your UDK cubes and create the convolved offline. There is a plugin called Diffuse_sh designed for that. It doesnt work for me. HDR Shop too, but my results weren't good. A sloppy solution would be a Blur in CubeMapGen... but it cant be correct.

I applied the trick to my translucent shader. The difference is barely noticeable due to the light algorithm I made there, but in a Lambertian one, is very notable.

Car Rendering

2011-12-23T17:38:00.000-08:00

Model by Cesar Martinez Álvaro

Translucency

2011-12-21T12:36:00.001-08:00

Full Size

Cloth

2011-12-19T14:27:00.000-08:00

New cloth shader. By adjusting parameters you can get a rough cloth like a towel, silk or velvet looking.

Full Size

Hitting the strings!

2011-12-07T11:21:00.000-08:00

Rock on! Doing something analogic is healthy :D
My first 'serious' song. Huge thanks to Victor Peral, performing keyboards and drums.
Composition, guitars and bass came from my hands.

Separation by David Miranda Gutierrez

UDK Populate. An Object placing tool

2011-11-17T12:07:00.000-08:00

Tool I've developed to help in the process of dressing a scene. The idea of this tool is to take the advantage of Max to place objects. By object painter script, scatter, physics... whatever the method you use.

New piece, a Container

2011-11-14T15:13:00.000-08:00

One more piece for the Oilfield. This time, with high poly version. Direct link

New site ready!

2011-10-10T15:11:00.000-07:00

At last i got my new site working. It was a nightmare, since I had to learn and make it by my self. Once more, the fact is: If you want something, do it by your self.
So, here is http://davidmiranda.me/

New Site and new content!

2011-09-21T17:52:00.000-07:00

HOT NEWS!
I will move my portfolio to a new site soon, with new screens, sections and... technical papers!!

Here is a preview of the new content i have been working in the last months:

Ocean and Sky Rendering in Unreal

The Oilfield. New remake

Scripts paper

Ocean Shader 2.0. Radial Fourier waves with 3 axis transformation

2011-09-02T21:18:00.000-07:00

Everything can be improved, so here is a much better Uber Ocean Shader for Unreal (Still in progress). Runs in dx9.
The pixel shader is quite trivial. Each color layer is controled with the distance between each pixel and the pixel behind. Currently im wondering the posibility of adding fog instead using z_Depth, as i did in the lighthouse. Reflections and other color controls are controled by a fresnel term. Specular uses the beckman distribution for atenuation, also using a Schlick's term and some other functions with the half vector.
There is also a chromatic aberration effect and a simple foam layer.

What i need now is better artwork :D

Many people ask me how in the hell i got those waves. Lets explain it:
The vertex shader is using what i call 'Radial Fourier waves with 3D transformation'. Signed, a freak xD
Currently, the waves are not just a modification in the vertical axis, but a modification in x, y, z to give them a real wave shape. At first, the movement didnt have in mind the world x, y position of each vertex, so all the waves peaks were going in the same direction. Now having in mind x and y in world space, my peaks are radial too. What about the implementation? Hehe, try it.
Published controls for the waves are: global amplitude, frecuency, world space 'scale' and 'real wave factor' which is in charge of making the nike logo, hehe. Also, the center of the radial wave.
There are also internal amplitudes and phases, but those are inside the Fourier serie definition.

Lets show the process by steps:

Radial Fourier waves with 3 axis transformation.

1. Get a Fourier serie working:

The first shape is just an example. Im using the triangle function for the final shader.

2. Radial movement:

Do you remember Mr Pitagoras? Use his law to make it moving radial

Sexy, eh.

3. The 'Nike' Shape:

Now im going to use the triangle wave. Gives the result im looking for.
The nike shape is just a modification of the Fourier serie. Then i got x, y, z. Remember you need to have into account the world position sign for each vertex. You dont want to apply the same transformation at every xy quadrant.
The separation you see at the center axis are due to the position correction. Maybe there is a solution for that. Its still a wip.

Good luck! :D

Future work:

Shore detection for uv's deformation. Useful for beach waves SOLVED
Foam layer at waves peaks SOLVED
Aditional variations of waves SOLVED
Static reflections to increase performance SOLVED

Future research:

Normal maps interpolation in accordance with wave shape. SOLVED
No camera-dependet fog SOLVED
Shore waves attenuation. z-Depth not available for vertex shader. Solved by vertex colors

Skin shader for Unreal

2011-08-02T15:44:00.000-07:00

Maybe the most research intensive shader i have ever made, full of workarounds to fake how light goes behind the skin and scatters.
Common methods are based on screen-space diffuse light blur. Since this is not possible in unreal, i had to find the way to get a similar result. The most common alternative are wrapped NdotLs to create layers wich are blended depending on the light vector.
The last change I have included has been a more physically accurate reflection model.
The BRDF used is the Kelemen Szirmay-Kalos, as proposed by NVIDIA.

Car Paint Shader

2011-07-22T15:58:00.000-07:00

Just for fun, i wanted to recreate this shader in unreal.

Some variations:

Featured by EPIC Games

2011-04-26T11:53:00.000-07:00

Great news!!, EPIC Games published my last project at facebook and twiter.

Thank you EPIC!!

Learning to Draw!

2011-04-02T13:27:00.000-07:00

Hehe... Today a mate at the office was talking to me about concept art and showing me related stuff. So i decided to try, why not to have a little fun drawing some easy and not interesting stuff? :D
So here is my first attempt:

#1:

But i still like programming!!

#2: Second attempt

#3: First Matte Painting!!

#4: Second Matte Painting:

EPIC Win, EPIC Fail

2011-03-19T07:12:00.000-07:00

Well, good and bad news. I found the way for adding new shader text files. But EPIC decided in the March build to not include source shader files anymore. That made me so angry, specially after discovering this.
I would explain how to do it, but since its not possible anymore it has no sense.

I defined two silly functions outside, just for testing. And there you see i can call them. EPIC WIN, hehe.

Exp3 is just a pow(float3, 3). And invert is 1-float3

And the EPIC FAIL goes to... EPIC! So... now Dx11, right? Hmm, ive seen almost the same graphics features than samaritan demo in Dx9. So... whats wrong? I prefer to move to Cryengine than wasting money on a new machine.

Im dissapointed.

Modifying Unreal Source Shaders

2011-03-03T11:42:00.000-08:00

Today, my challenge was accesing to unreal shader sources. Its possible to modify them! (Will be possible to add new(text based) ones? Ill try). My first goal was easy, just to DELETE once and for all the odd phong specular model and using Blinn instead. If you know unreal, you know the listbox in the Material editor where specular models are listed, MLM_Phong, MLM_Unlit and all the family. I changed the name too. I wanted to add my new one, but its not possible without having acces to the C++ source files. If you take a look at the generated HLSL window, youll find this bad new:

Defined by the C++ code:

[...]

MATERIAL_LIGHTINGMODEL_PHONG

MATERIAL_LIGHTINGMODEL_NONDIRECTIONAL

MATERIAL_LIGHTINGMODEL_UNLIT

MATERIAL_LIGHTINGMODEL_CUSTOM

MATERIAL_LIGHTINGMODEL_ANISOTROPIC

[...]

So i can only use those slots :/

I have never understood, why a supposed 'next-gen' engine insists on using the old-poor-nonreal phong specular model. Blinn is not much more expensive, less than 10 more instructions and looks closer to real life.

So, here is a comparison between my hardcoded Blinn and the node-based one:

Exactly the same than the hardcoded one:

A new world discovered!

Ocean Waves

2011-02-23T15:38:00.000-08:00

Most of the people never found math useful when they studied it at school, but it is!! Today i decided to fix my ocean waves, and i designed 2 pretty cool functions to create better waves.

The Magic of UP-Vector and Fresnel Reflections

2011-02-19T10:44:00.000-08:00

This time i used the Up-Vector to create fresnel reflections and a Dust layer. Specular and Fresnel Reflections are masked by the dust layer.

Here is the result in the Oil Field:

Tweaking Values:

Ibanez Jem in Unreal

2011-01-24T15:46:00.000-08:00

This time, ive imported to Unreal the guitar i made some months ago for a render. I used my postprocess shaders and for materials i have used the Oren-Nayar Cook-Torrance Models for almost everything.

Relief Mapping

2011-01-18T11:25:00.000-08:00

I should call it AWESOME MAPPING!
Here goes the most hard Shader of my collection. Credits goes to ATI, Nvidia, Ben Cloward and to Christopher "IndependentSoul" Schiefer for the Camera Vector x (1, -1, 1) trick.

Using this technique... the result is awesome:

Go to picasa album and <-- -->

Using with decals:

Oren-Nayar Diffuse Model + Cook-Torrance Specular Model

2011-01-16T11:04:00.000-08:00

Another goal reached:

Target: Metals and Plastic. Oil Field metals!, lets Rock!

Oren-Nayar Diffuse Model + Blinn Specular Model

2011-01-16T07:49:00.000-08:00

The default Diffuse Model in Unreal is Lambertian, wich is quite poor and dull. Here is my improvement with Oren-Nayar diffuse model:

Lambertian Diffuse model + Blinn Specular Model:

Oren-Nayar Diffuse model + Blinn Specular Model:

Blinn Specular Model

2011-01-12T15:02:00.000-08:00

Well, since Unreal doesnt incude this specular model, it was a 'must do' to add it. I have added it to my master parent material to add it to all of its sons ;)

An ambient component was added to the specular.

Anamorphic Lens Flares

2011-01-07T08:55:00.000-08:00

Custom Depth of Field (DoF)

2011-01-06T02:06:00.000-08:00

Edit

Improved method. The blur algorithm has been modified. Now is texel based and 2 z-Depth maps are used to focus at certain distance. White is blured, black is focused:

Lens Distortion

2011-01-05T16:58:00.000-08:00

This effect emulates the behaviour of lens distortion with the resulting color aberration. Changing values, the shader can recreate different styles of distortion; cubic (pincushion,barrel) or radial.
The more the distortion, the more the color aberration.

Natural scene, without any postprocess:

Full processed:

Chromatic Aberration

2011-01-05T13:14:00.000-08:00

Bad camera lens create an effect called Chromatic Aberration, wich causes noticeable color artifacts specially at shapes borders with a strong light contrast. Its due to the different index of refraction for different wavelenghts of light in the lens.
The effect is distance dependent. That means, the artifacts increase with distance. It has also been blured, to fit with the real behaviour.
So here is my aproximation:

Comparison:

Custom Antialiasing

2011-01-03T16:16:00.000-08:00

After looking for methods to get antialiasing, i found an useful idea. This method mix a blured image with the original one using a mask. Which mask? A mask wich paints the geometry edges.

#define All_images_scaled_200%

Original Image:

Here is the mask. It has two detection methods; it paints first the edges inside the shape, and then the outside ones, to allow blurring on both sides:

Then, i needed to blur the original image. The blurring method was pretty simple. Inside a loop, i displaced the image both horizontally and vertically, adding each displaced image to the original one. Then i divided the result by the number or reiterations in the loop. This is the result:

And the desired result:

Another example:

Programming HLSL Shaders

2010-10-23T20:38:00.000-07:00

Well, at last i started learning some funny HLSL stuff. Im currently focused on developing real life lens, photography film behaviour, and other post-process effects.

Bleach Bypass

Cross-Processing

Sky God Rays

The rays effect is applyied to a texture, its not a postprocess.

HDR

My MaxScript toys

2010-10-23T14:37:00.000-07:00

FumeSleep:

This tool is designed to run FumeFX simulations without being present. Hit and run :D I didnt like to spend hours checking when the simulation was finished to start rendering frames. So i made this tool to make everything with just one click. When the tool starts, it looks for the FumeFX volume, selects it and opens the UI. You can also select the volume by pressing its name in the list box. If the UI is closed, when you clic the listbox, its opened. The tool can simulate, render and hibernate the computer once everything is done. So, just clic 'Do it!' and go to bed ;)
By pressing refresh it searchs again for the FumeFX volume in case you created it later, or deleted the old one.

FumeSleep .NET version:

Time ago i wanted to check out the possibility of calling .NET controls from maxscript. Archieve Unlocked :D

Taking the advantage of .NET controls, i added some extra functions, like that balloon showing some useful info or the tray icon.

New Open File Dialog:

I always hated the default 3ds open file dialog, so here is an interesting fix:

I made the same for file impoting - exporting.

Copy-Paste Objects:

Save Selected and Merge to another 3ds instance can be unconfortable, so lets make that with just 2 clics:

Export layer to files:

This tool exports the content of your layers to a folder. You can add and save paths. When you run the tool, all your stored paths will be listed in the list box. Just select one. It will export one file per layer with the layer name.

Paint Object Tool:

Sometimes, in a 3D scene you may need some kind of help to avoid gettin' crazy on repetitive processes. An example is when you need to duplicate an object over another many times. For example, when placing grass on a large ground. So i developed a tool to do this using the mouse. The tool allows you to place your source model perpendicular to the surface or just vertical, useful for trees. You can also rotate the model by clic/drag/release to finish the copy.

Fix texture path:

I had to develop another tool for StimmyGames. The engine needs relative texture paths. Something like /Engine/Textures/color.dds but max exports C:/Game/Engine/Textures/color.dds
The engine is integrated in Maya, so i export the models from 3dsMax in FBX format with the fixed paths.

Here is the description document

Unreal Export Tool (WIP):

Sometimes, when you have to export several files it could be exhausting. So here is another 'One Clic' tool:

Unreal 3 Collision Tool (WIP):

Well, Unreal is amazing, but... it doesnt support the visual mesh as collision mesh. So, what to do when you have an imported terrain from an external 3D package. You will want to walk over it. Well, this a problem for me, since i never use its terrain tool for my terrains. But i can generate collision boxes in one clic:

It generates a Box with the template name UCX_ObjectName_Nº in each polygon. The UCX prefix tells unreal 'this is a collision box.
The tool can also create bounding boxes or spheres.
Anyway, this is quite crazy if you dont make an optimized mesh before doing this. So selecting the walkable surface and optimizing it is a must do.

The Lighthouse

2010-10-12T10:17:00.000-07:00

As starting point, i have made a base mesh to sculpt it later in Zbrush (One of my first sculpts)

The rock shader contains 6 different color maps; rock and sand textures, a normal map baked from the high poly version and a color map wich includes a modified cavity map, ambient oclussion and color variation blended like a photoshop 'Soft Light' blend mode.
Here is a comparison between photosop Soft Light Blend mode and my color map in my shader (almost the same ^^):

The textures blends using masked per-vertex colors to avoid the typical 99' soft blend.

I also added a fresnel effect and a grey mask to add a wet effect to the rocks wich are in contact with the water. The wet zone is animated using some math operations and custom hlsl. It follows the sea height.

The water foam is animated modifying its UV's using the same transformation of the sea height and wet movement.
The ocean mesh is animated via vertex shader wich reads data from a wind entity and math operations to create the waves.

So lets see it moving!

Also available on vimeo

... Its late for the Oil field rocks :/

Edit: 23.10.2010

For so long, i have had a personal challenge. Its called HLSL!!! So, i have started playing around, reading msdn, hitting my head against the screen... and here is my first post production Xtreme sharpen effect:

Edit: 28.10.2010

Today, i tried to add foam layers/small waves to the beach. I had to code a custom node in HLSL that allows to pan a texture only in one direction. Atm, i have only worked well in the codding aspect. The texture is still quite bad (fast made), with no visual effects added at all.

The custom node has 3 inputs: the texture to pan, the uv's and the offset to apply to uv's. This offset comes from a sin*cosin operation wich moves at different speed.
This operation is smoothed to avoid extreme values. This sin*consin function is also used to control the wet zone movement and the water mesh height, so that means everything dance together :D!

Lighthouse built!. Check it here

Edit 08.11.2010

Sky God rays. Its sky time. First, i implemented a god rays post process. But i didnt find it useful, i dont want to apply the effect to the whole screen. So i tried to implement a god rays effect in a texture. And here is the result:

The problem is that the rays are cut with geometry edges :/

Edit 10.11.2010

New model of boat. The lighthouse man needed it :D Check it here!
Footsteps in the beach
Cross-Processing PostProcess codded in hlsl
Added group of birds flying

Edit 15.11.2010

Added HDR based on Reinhards operator.
Added background land

Edit 20.11.2010

Its almost done!
Javi Neiro is animating a Crab modeled by 3D artist Pablo Poliakov .

Edit 28.03.2011

At last those lazy guys finished my crab!!
New video released and finished project!!

UDK Ocean Shader

2010-10-03T15:10:00.000-07:00

Well, i have started with the Lighthouse, and what better to start with the sea? Its a subdivided mesh moved via vertex shader and also influenced by a wind entity, so it has plenty of life.

My first concept art

2010-10-02T13:45:00.000-07:00

After spending some days in Jandía, Fuerteventura, i started thinking in the lighthouse i saw there and the possibilities of making some related 3D art.
I also know i should sketch my art before starting modeling important stuff. So here is my first attempt on concept art.

Full Resolution

Struggling to live

2010-09-05T12:16:00.000-07:00

Lets add some green life and hopes after the brown 'nex-gen' oil field...
This is a piece of art that I created for an unannounced title being developed by StimmyGames which have contracted me as a freelance artist doing 3d modelling as well as technical tasks. As the project moves forward my role is moving towards a more senior art position where I establish art lines as well as design and develop my own art pieces.

Technical Info.
The low poly version of the rock have been made in 3ds max. A very very simple mesh. The high one, in Mudbox. After testing mudbox, i think maybe i still prefer ZBrush for sculpting. I missed some Z brushes i love. But Mudbox is still more confortable, since you can configure it, as for example, 3ds max.
I made the tree trunk in ZBrush, using ZSpheres, and sculpting a little bit later. Low poly version made with DecimationMaster.
Rock texture and trunk have been made in Mudbox. Mudbox +5 Bodypaint -10 hehe.
Rest of art, standard modeling in 3ds max.
Rendered in unreal, just for testing.
Amount of time, about 15-20 h

Oil Field - Unreal Engine

2010-05-09T17:08:00.000-07:00

I met Unreal when working in the Pyro Studios art department along 2008. I fell in love with this technology since the first day, so once i learned enough, i decided to start building my own scene.
I have been working on it about 15 months, in my free time, making every element of the scene. From the idea to the final scene.
Its still unfnished, so it will improve in the future.

Newer Screens:

Movie and Cinema Browser

2010-04-04T18:41:00.001-07:00

Well, this is a final course project, and I wanted to show off and expand knowledge.
The application allows you to see what cinema you can watch the movie you are looking for.
The program works reading the information from an access database.
Of course, it allows you to search for movies. When the movie is found, it's shown in a list. Then, if you select it, automatically plays its trailer, shows the overview and the cinemas with some useful info.

After Effects Post Production

2010-03-02T16:37:00.000-08:00

Well, since ive found photoshop poor for postpro, ive decided to try a soft specifically designed for these tasks. So here is my first attemp with After Effects

El Enigma de la Abadía

2009-12-27T16:54:00.000-08:00

Well, i've joined this team these days. They want to move the game to unreal engine. So, somebody out there talked about me for the dirty job xD
Im in charge of mesh/materials setup/exporting, shaders, postprocessing, lighting, particle effects... and every technical aspect.
These images show the first steps.

And lets see it live!

Casino La Laguna, Tenerife

2009-10-01T19:25:00.000-07:00

Ibanez Jem

2009-09-14T15:49:00.000-07:00

This is a custom designed guitar based in the Ibanez Jem Series. I fell in love with this design, so i customized my own guitar to approach its looking to this one, hehe.

Fountain

2009-09-13T06:39:00.000-07:00

Bic

2009-09-10T17:46:00.000-07:00

Coffee

2009-09-01T07:12:00.000-07:00