Rendering design prototypes for many materials can become easy once you learn to predict how the material will behave in given lighting conditions. However highly reflective and transparent materials are much harder to predict – glass, in particular. That said, I notice many marker visuals for perfume bottles and glass products online that have been rendered very well without a reference (see Fig. 1-3). This leads me to believe that glass can be understood well enough to create convincing design constructions & prototypes if one knows how. Are there any rules to help me understand how light behaves on glass objects? i.e. How do shadows & highlights behave on glass? How can I anticipate the shape of reflections on a glass object? Does convex or concave glass effect how shadows/highlights/reflections are formed respectively? It seems that light is hardest to predict where glass is thicker, or where curves & edges occur. I would like to be able to draft glass design prototypes that are more convincing, without the limitation of existing glass references. I’ve included some examples below which demonstrate glass prototyping very effectively. These were designed by Sangwon Seok & Begüm Tomruk (see references & links below). Image References:
- Sangwon Seok, (2014), Product Sketch [ONLINE]. Available at: https://www.behance.net/gallery/product-sketch/14568139 [Accessed 5 September 2016].
- Sangwon Seok, (2016), Product Sketch [ONLINE]. Available at: https://www.instagram.com/p/BFV65usOEp8/ [Accessed 5 September 2016].
- Begüm Tomruk, (2011), I.D. Sketching & Marker Rendering [ONLINE]. Available at: https://www.behance.net/gallery/1176939/ID-Sketching-Marker-Rendering [Accessed 5 September 2016].*
Glass Rendering Tips with D5 Render for Realistic Architectural Visualization
It is an established fact that realistic glass rendering in architecture is necessary for the success of every design project, but the truth is it’s not very easy to achieve. The properties of glass like reflection, refraction, and transparency make it a very difficult material to render. Fortunately, real-time rendering software D5 Render understands and caters to the needs of all designers and architects. Thanks to its efforts, achieving lifelike glass texture in D5 Render only takes several clicks. Forum.
Before you get down to glass rendering in archviz projects, there are several things to keep in mind.
1. A nice overall atmosphere of the scene is a Must
Remember that a harmonious scene is the core of realistic rendering. How glass textures should look depends on what kind of atmosphere you want to deliver. Say we won’t choose pilkington texture glass for the facade of a modern office building, so make sure to first adjust the general atmosphere of the scene.
In D5, we can create a satisfactory global lighting effect with HDRI/Geo and Sky in the Environment system. With a few adjustments and preview, you’ll get to the vibe you want.
To add your character to the visual, you can choose a suitable LUT from D5 or from your own collection. Exposure, Contrast, White Balance and more post-processing parameters are available right inside of this renderer, so you don’t need to go to Photoshop or other photo-editing tools.
2. Choose the right glass texture from D5 Material Library
You can choose what you need from the D5 Asset Library, which has dozens of default glass materials, such as pilkington glass, tinted glass, frosted textured glass and more.
D5 Asset Library – Glass Textures (More to come)
You can also use the Transparent material template inside D5 Render, which gives great glass effect with a few tweaks.
3. Useful glass reflections trick with plane model from D5
Did you ever struggle to get the bright and clear reflection of glass textures? Keep getting those dull black shadows cast by surroundings after adjustment of sunlight and sky to serve the glass wall? Here’s where a plane plays magic:
First we need to add a plane asset from D5 Asset Library, and place it in front of the glass facade that shows reflections of its surroundings.
Then attach to the plane a map of sky so that we will have an “artificial” sky board on the exterior of the building. Adjust the Offset parameter to see if the sky map is properly placed.
Now the glass reflection may look better but far from good due to the darkness of the sky map.
Lighting it up by making the plane emissive is a good idea. Remember to turn off the “Cast Shadow” button because you don’t want it to influence other buildings. After adjusting the Intensity parameter to make the sky map properly lit up, we are only one step away from making it.
As you can see, there’s refelction of another building behind on the glass facade, which is coming from the plane. To eliminate that unnecessary reflection, select the material of the plane, pull Specular and Metallic parameters to the highest and Roughness to the lowest. Now everything looks great.
4. Pay attention to what you see through the glasses
The glass texture is charming in architectural visualization because it allows lights to come through the facade, making a vibrant scene. Nobody likes to see black holes behind glass windows.
To quickly furnish the inside space of a building, we need to use the plane again. The whole process is quite similar to what we did in the third part.
1, Drag and drop a plane into the scene, scale it properly to cover the area of glass facade you need.
2, Add a night scene map to the plane and turn on Triplanar, adjust UV and make sure the texture mapping is correct.
3, Try to think about the real world we live in. We can only see what’s behind a glass window when the inner space is bright enough. It works the same way with 3d rendering. So what we need to do is turn on Emissive to illuminate the plane and adjust its intensity as you like.
4, Now place the adjusted plane behind the glass wall.Here you go! A stunning glass building is ready to render.
Introduction
Hello everyone! I’m Cem Tezcan, a freelance technical designer from Turkey. In this breakdown article, I will give some tips on how to create refractive materials in Toolbag 4.
I created bottles and liquid models using subdivision modeling techniques in Modo. After completing the models, I froze the geometry to create perfect curvature with a high poly result.
There are some important things to consider while creating this type of geometry. The first is to add thickness to the bottle geometry.
Next, I created liquid geometry inside the bottles by copying and pasting the inner facing polygons and recapping them.
An important detail of ray tracing is that liquid geometry and bottle geometry cannot overlap. Otherwise, you’ll see strange artifacts in the renders due to intersection errors. The liquid geometry needs to be enlarged to sit in between the bottle’s outer and inner facing geometry to solve this issue. If the liquid is smaller than the inside of the bottle, the refractions will be wrong.
Toolbag Scene Setup
I exported my models as an .FBX file and imported them into a new scene in Toolbag 4. Before moving forward, I made sure to turn on Ray Tracing under the Render settings.
Cork Material Creation
I added a new Texture Project to the Scene hierarchy to create a cork material. I added a Beech Spalted Varnished material from the Library to the Layers window and set the Projection Method to Tri-Planar with 2x tiles.
Next, I added a Fill Layer with a black color, zero Metalness, a high Roughness value, and a low Bump value. Values lower than 0.5 for Bump equates to cavity detail. This layer will create darker scratches with cavities, according to the mask I will assign.
I added a Fill Layer to use as a mask for the black Fill Layer. I used the Grunge Scratched texture from the Grunge Maps folder. I set the Projection Method to Tri-Planar and the tiling to 6x. I adjusted the Mask opacity and Contrast to control the scratch intensity, which created an organic, worn-out look to the cork material.
Liquid Material Creation
Liquid materials are simple to create. To start, I defined a color for the liquid and then set the Transmission module to Refraction. I adjusted the Scatter and Density values, lowered the Roughness, and changed the Reflectivity module to Refractive Index. I adjusted the Index value to 1.4 to create an olive oil looking material.
I used the same material setup for other liquids and set them to different colors and scattering values. Keep in mind that the encasing glass will affect the final appearance of the liquid.
Bottle Material Creation
I created new Texture Projects for each bottle. Starting with the large bottle, I created and linked a material on the left side panel. In Active Maps, I activated the Metalness and Roughness maps and changed the Transmission module to Refraction. Similar to the liquid materials, I changed the Reflectivity module to Refractive Index.
Now I can start adding layers for the glass material. First, I added a Fill Layer to act as the glass’s main material and set the Roughness and Metalness values to zero. Remember that these channels are connected with the linked material that is assigned to the 3D geometry. Since the linked material has its Metalness module set to Refractive Index, the textures in our Layers window will be transferred directly to the linked material and generate refractive results.
Second, I added a Fill Layer and named it Glass Imperfections to create imperfections since most manufactured glass products have a slightly wavy surface that produces bent refractions. To start making this effect, I enabled the Bump channel and gave it a value of 0.488.
Then I added a Perlin noise procedural mask to the Glass Imperfections layer. I adjusted the Scale under Perlin Settings and set the Projection Method to 3D.
This results in a light waviness, which can be seen by looking into the refractions.
I added another Fill Layer and named it Damages, which was used to add some detail in the Roughness and Bump modules. Despite defining it as a damage layer, it generates low-quality manufacturing details of the glass, similar to old bottles and windows. I set the Roughness value to 0.3 and added a high Bump value. As you can see on the Layers panel, I set the Blending for the Bump channel to Multiply to preserve the Perlin noise waviness I generated on the previous layer.
I layered multiple masks for this damage layer. I used the Dirt Surface Grunge Texture from the Library for the first layer and set it to a Tri-Planar Projection. Above this, I added a Paint Layer and manually painted out the dirt detail from the inside, isolating it to exist only on the outside of the bottle.
Layering Water Droplets
The final step in the texturing process was to add my procedural droplet generator, which can be found on my Artstation Store. This Substance file creates procedural, random, and adjustable droplets with 2 parameters. You can export several variations of the droplet texture using Substance Player. I exported my droplet textures in 2k resolution.
I applied the droplet textures to the active maps in my texture project, Albedo and Normal, and set their Projection to Tri-Planar. Since the liquid color is green, I changed the Albedo color so that the droplets have a green tint to them.
I needed to isolate the drops to exist only outside the bottle and above the liquid. To do this, I added a paint layer as a mask and used the rectangle marquee selection tool to isolate the area I wanted to paint. I switched the camera to a front view and selected both inner and outer surfaces of the bottle, then deselected the outer faces in the Canvas window.
I used the Dust brush preset from the Library to paint some organic edges on the harshly masked edge in the Canvas window. In the Brush Settings window, I set the Projection of my brush to UV since the inside of the bottle’s UV is inverted. Trimming the top caused drops to be trimmed from the underside. I must say, the ability to use a selection tool in a 3D viewport is an amazing feature!
For a final touch, I added moisture on the glass’s surface by adding a fill layer with the Roughness Map activated and a value set to 0.725. I added a Mask with a Dirt Processor to the Fill Layer, which helped create the glass’s moisture.
This is the final look of the bottle. I later applied the same steps for the rest of the bottles, with some differences in colors and textures.
Learn how to use Texture Projects in Toolbag
Creating a Cut Crystal Bottle
I created a procedural cut crystal pattern with Substance Designer for the last bottle and applied the normal and roughness maps on the glass’ outer material.
Chapter II, a lighting setup
In photography there are a lot of techniques to make something bright or dark, while photographing jewlery, wine bottles, parfumes.
The basic idea is to setup a series of white reflective pices of cardboard, and black ones, to make interesting reflections, either on curved faces or flat ones.
This is an art on itself, take a look on some youtube tutorials, like this one: https://www.youtube.com/watch?v=JP3ykBzk_RU and see, that the resulting image is in reality a composition of the surrounding areas.
Inclusive in photography there are a million ways to put the light on one single glass to make it look diferent and atractive.
Chapter III
Freedom, you are an artist!
The point is not reflection-refraction acuracy, but an artistic interpretation to give a general idea of the final product.
Make some decisions, what face will be the happier bright one?
And build on top of that. This will be darker, I need contrast here, I need a simulation of a dark refraction, I want a nice Highlight here or a gradient there.
Chapter IV
Forget all my post and go and draw!
I am exploring this same topic a bit more in depth for a “Gold material” here:
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answered Sep 9, 2016 at 8:37
Rafael Rafael
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Excellent answer @Rafael. I’m going to leave the question open though for more contributions just until the bounty has almost expired. I thought the (1)Gloss-e&f points were very helpful. I assume this applies to metal too? (2) Transparency cons. of energy is helpful to know too. In a hollow perfume bottle e.g., will the inner highlights still follow this law or change, as they are still viewed through one glass side? Thanks for your help 🙂
Sep 9, 2016 at 9:27
Also out of interest, what 3d software do you use to render these prototypes with?
Sep 9, 2016 at 9:31
The cube was made with blender with cycles render engine. The second, helixes, were rendered with kerkythea. – Of course, leave the question open, It is a very interesting one. – I need to expand further to an effect called Fresnel. Also I will expand the diference between metalic an non metalic reflection.
Sep 9, 2016 at 14:05
-.- I’m going to end up giving more rep to you aren’t I. Rafael, Bounty Hunter lol
Sep 12, 2016 at 0:11
Lol. Ryan I thought about it. But the point is that you have a good eye on bringing atention to interesting questions. Really n_n. I am not an ilustrator, probably a frustrated one, that is why this themes grab my atention a lot.
Sep 12, 2016 at 0:21
As with many questions of this nature, there are three requirements: practice, practice and more practice. That said, there are a couple of tips that I can share from my experience and struggles with illustrating product designs like those that you have shown. My approach has always been via digital illustration (Illustrator or Photoshop), but the same applies for hand drawing.
Firstly, you need a prolonged scheme of recreating the appearance of glass from existing sources. This can be based on photographs or other peoples illustrations. Trace, copy and duplicate as many different, relevant glass objects as you can find until you identify the methods that work for you. Don’t underestimate the value of doing the same one over and over again to refine and speed up your skills.
Secondly, glass (and transparent objects in general) can be broken down into four components and approaching them as four separate layers or stages has helped me a lot:
- The SHAPE of the object. This is the obvious place to start. Depending on your style, this might be an outline, a few highlights and shadows, the shadow cast on a surface by the object and maybe a subtle (or not so subtle) tint to represent the colour of the material.
- The things that can be seen THROUGH the glass. This is the most complex part. Anything behind the object needs to show through, but you need to consider if you want to distort that object to simulate refraction. This is not always necessary, but can add a significant twist of extra realism. You will usually be able to see the back and inner faces of the object itself. These should be drawn in the same style and colour as the object, but will generally by less opaque to show that they are secondary features.
- There may well be a liquid or product INSIDE the container. You need to consider how the colour and general appearance of the contents will be affected by the container. The contents itself may be transparent, in which case the opacity of that needs to be taken into account as it may obscure object behind the container more than the container does. If the contents only partially fills the container then it might need a visible surface as part of its own shape.
- Finally (and I would usually do this last), there are the things that are REFLECTED in the surface of the glass. You will always want to add a few highlights – soft and subtle on the flat surfaces and harder, brighter catch lights at corners; and maybe some darker areas to suggest the general reflexion of the environment. If there are multiple objects in the scene then showing a subtle reflexion of nearby items in the surface can add more realism and really the knit the scene together.
Some of this is probably obvious, but if you break it down as I have, then you should be able to find your own solution for each component and then build them up into your own style of illustration.
Personally, I often resort to 3D modelling and rendering software for this kind of project, but that’s just a personal preference. Sometimes I will produce a 3D render and then work over the top in photoshop to add my own touches.
