1 Introduction
Cem Tezcan is a technical artist from Turkey. In this categorical article, some tips on how to create refractive materials in Toolbag 4 will be given.
2 Modeling of bottles and liquids
I created a bottle and liquid model using subdivision modeling techniques in Modo. After finishing the model, I froze the model to create a perfect curvature with a high modulus effect.
There are some important things to consider when creating this type of geometry model. The first thing to consider is to add thickness to the bottle geometry.
Next I made new models inward by copying and pasting the faces, readjusted them, and then created a geometry model inside the bottle as a liquid.
An important detail to use ray tracing is that the liquid geometry and the bottle geometry must never overlap. Otherwise we will see strange imperfections in the rendering due to an intersection error. To solve this problem, it is necessary to expand the liquid geometry so that it is located between the outer and inner surfaces of the bottle. Because if the liquid is smaller than the inside of the bottle, the refractive index will be wrong. Therefore, a total of three layers must be made, the inner surface - liquid - the outer surface.
3 Eight Monkeys scene setting
I exported my model as . FBX file and import it into a new scene in Toolbag 4. Before continuing, I made sure to enable Render settings under Ray Tracing.
4 Cork material creation
I added a new texture project to Layers to create a cork material. I added a beech spalted Varnished material taken from the library to the Layer window and set up a three-plane projection with a 2x texture map using the projection method.
Next, I added a fill layer with the layer set to black, metalness set to 0, roughness set to a little higher, and then the bump value set a little lower. When the convex value is less than 0.5, it can be regarded as a detail of the inlay. Depending on the mask I specified, this layer will create darker scratches with inlays.
I added another fill layer to serve as a mask for the black fill layer. I used the Runge Scratch texture in the Runge Maps folder. Set the Projection Method to Three Planes and tile to 6x. I adjusted the opacity and contrast of the mask to control the strength of the scratch, which created an organic, shabby look for the cork material.
5 Liquid material creation
Liquid materials are easy to create. First, I defined the color of the liquid and then set the transmission module to refraction. I adjusted the scattering and density values, reduced the roughness, and changed the Reflectivity module to Refractive Index. I adjusted the index value to 1.4 to create a material for the appearance of olive oil.
I used the same material settings for other liquids and set them to different colors and scattering values. Keep in mind that sealing glass affects the final appearance of the liquid.
6 bottle material creation
I created a new texture project for each bottle. Starting with the large bottle, I created and linked a material on the left panel. In the active map, I activated the metallicity and roughness maps and changed the transfer module to refraction. Similar to liquid materials, I changed the Reflectivity module to Refractive Index.
Now I start adding layers to the glass material. First, I added a fill layer as the primary material for the glass and set the roughness and metallicity values to zero. Remember that these channels are connected to the linked material assigned to the 3D geometry. Because the Metalness module of the linked material is set to Refractive Index, the texture in the Layers window is transferred directly to the linked material and produces refraction results.
I then added a fill layer and named it "glass blemishes" to create the imperfections, because the surface of most glass products produces a slight wavy shape due to manufacturing, resulting in curved refractions. To produce this effect, I enabled the bump channel and set its value to 0.488.
Then I added a Perlin noise program mask to the glass artifact layer. I adjusted the scale under Settings and set the projection method to 3D.
This creates a slight ripple, which can be seen by looking at the refraction.
I added another fill layer and named it "Broken" to add some detail to the Roughness and Bump modules. Although defined as a layer of damage, it produces some sort of low-quality glass-making detail, similar to old bottles and windows. I set the roughness value to 0.3 and added a higher bump value. As you can see on the Layers panel, I set the blend of bump channels to "multiply" to preserve the Peilin noise ripple I generated on the previous layer.
I divided this damage layer into multiple blend layers. I used the dirt surface rough texture in the library in the first layer and set it to Tri-Planar. On top of this, I added another layer of paint and manually drew the dirt details from the inside, isolating it so that it only existed on the outside of the bottle.
7 water droplets are layered
The final step in the texturing process is to add my procedural waterdrop generator, which can be found in the store at Station A. The substance file uses 2 parameters to create procedural, random and tunable water droplets. You can use Substance Player to export multiple variations of the waterdrop texture. I exported the droplet texture at a resolution of 2k.
I applied the waterdrop texture to the active maps in my texture project Reflectivity and Normal and set their projection to Three Planes. Because the color of the liquid is green, I changed the color of the reflectivity so that the droplets appear green.
I need to isolate the droplets so that they only exist outside the bottle and above the liquid. To do this, I added a paint layer as a mask and used the Rectangle Marquee tool to isolate the area I wanted to draw. I switch the camera to the front view, select the inner and outer surfaces of the bottle, and then deselect the outer surface in the canvas window.
Using the Dust Brush preset in the gallery, I draw some organic edges on the rough mask edges in the canvas window. In the brush settings window, I set the projection of the brush to UV because the UV inside the bottle is flipped over. Trimming the top will cause the water droplets to be trimmed off from below. I have to say that the selection tool in the 3D viewport is an amazing feature!
In the final step, I added moisture to the glass surface, added a fill layer, and the roughness map was activated, and the value was set to 0.725. I added a mask with a dirt processor to the filler layer, which helps to make moisture on the glass.
This is the final appearance of the bottle. Later I applied the same steps to the rest of the bottles, only in a different color and texture.
8 Make cut crystal bottles
I used Substance Designer to create a procedurally cut crystal pattern for the last bottle and applied normals and roughness maps to the exterior material of the glass.
9 Finish rendering setup
I used a large plane as the ground and specified a high tile value. I chose "Train Station Platform Overlooking the Sky" from Curry and turned up the brightness to the ideal exposure. Since the ground has a dark reflective material, I set the background brightness to 0 to create a black background. I enabled depth of field in the camera settings to blur the horizon. Despite this step, the horizon remains clear.
I added a fog object and set its color to black, which is an easy way to further blend the scene.
10 summaries
I hope you enjoyed this category. Thanks to the new ray tracing system, Toolbag 4 can easily handle organic refraction effects. Drawing tools make it interesting for us to see the effect of a real photo when we draw in real time. I like this version very much and hope you all enjoy it too.
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