In my last post, I went through a method of creating a simulated reflection with a simple scene. This time I’d like to take the technique and apply it to something a bit more realistic. I have a model of a car that I’d like to show off in KUESA, and as we know, KUESA doesn’t render reflections.

Using the method discussed last time, I’d need to create an exact mirror of the object and duplicate it below the original, and have a floor that was partially transparent. This would be expensive to render if I duplicated every single mesh on the high poly model. Here, the model is X triangles – duplicating it would result in Y triangles – is it really worth it for a reflection?

However, if I could take a low poly version of the mesh and make it look like the high poly mesh this could then work. I could bake the materials onto a low poly mesh. Easy to do in blender.

Here I have a low poly object as the created reflection, with the baked materials giving the impression of much higher detail than physically exists. Using the same technique of applying an image texture as an alpha channel, I can fade out the mesh below to look more like a reflection.

To further the illusion, I can also blur the details on the baked materials – this, along with the rough texture of the plane, gives more of a reflective look, especially when you consider that a rough plane would not give an exact reflection:

The good news is, it produces an effect similar to a reflection, which is what we want.

This is all very well for a static model, but how can I deal with an object that has animations, such as a car door opening? I’ll look into this in the next post.

The post 3D – Interactions with Qt, KUESA and Qt Design Studio,<br>Part 2 appeared first on ACuteDesign.

KUESA

I’m a 3D designer, mostly working in blender. Sometimes I come across interesting problems and I’ll try to share those here. For example, trying to display things on low-end hardware – where memory is sometimes limited, meaning every polygon and triangle counts; where the renderer doesn’t do what the designer wants it to, that sort of thing. The problem that I’ll cover today is, how to easily create a reflection in KUESA or Qt 3D Studio.

Neither KUESA or Qt 3D Studio will give you free reflections. If you know a little about 3D, you know that requires ray tracing software, not OpenGL. So, I wondered if there would be an easy way to create this effect. I mean, all that a reflection is, is a mirror of an object projected onto a plane, right? So, I wondered, could this be imitated?

To recreate this, I’d need to create an exact mirror of the object and duplicate it below the original, and have a floor that is partially transparent. I’ve created a simple scene to show you how this technique works – a scene with two cubes, a ground plane and a point light.

Here’s the result of this scene. It’s starting to look like something, but I want to compare it to a ‘real’ reflection.

For comparison, the above is a cube on a reflective, rough surface – showing the result using raytracing. You can see here the reflection is different from our example above – the main issue is that the reflection eventually fades out the further away it gets from the contact point.

How to resolve this? This can be mimicked by creating an image texture for the alpha that fades out the model towards the top (or rather the bottom) of the reflection. I can also further enhance the illusion by ensuring that the floor is rough – allowing the texture of the surface to assist the illusion of a reflection.

Another difference between the shots is the blurriness on the edge of the mesh – this could be approximated by creating duplicates of the mesh and for each one, increasing the size and reducing the opacity. Depending on the complexity of the model, this may add too many polygons to render, while only adding a subtle effect.

So, given that this is a very simple example and not one that would translate well to something that a client might ask for, how can I translate this into a more complex model, such as the car below? I’ll chat about that in the next post.

The post 3D – Interactions with Qt, KUESA and Qt Design Studio,<br> Part 1 appeared first on ACuteDesign.