What a Mesh

Rendering in AutoCAD part 2

Hi,

after a long time with no posts (partly holidays, and too much work), let's continue talking about rendering in AutoCAD.

Let’s check the rendering of this bathroom.

 

 

The camera is clearly at a corner of the room, targeting the opposite corner. This gives a focal point to the shower, which also has an interesting (I hope) illumination.

The foreground shows an ornament (transparent, so it can add some coloring and interesting refractions) over wood and the Jacuzzi.

 

I also thought wood and the white glossy surface of the Jacuzzi would be an interesting contrast that livens up the foreground. In order to get some attention over those elements, I chose to show sunlight coming from the outside from a window that is not in the scene. But the window could have been opened, and generate a lot of light. In this case, the choice was to use the blinds in order to filter that light, and also cast some shadows that emphasize the curvature of the Jacuzzi. It also helps to establish another point of interest on the ornament and the Jacuzzi itself. That said, the windows are not in the scene, but I brought them in through their reflection in the mirror. The artificial lights over the mirror also give some more emphasis to the linearity of the drawers, sink, etc, located in the back wall. It definitely helps to make the bathroom feel longer than it really is.

 

So a lot is going on in this scene, which at first could have been thought as just another option for a camera in the bathroom.

 

Creation of materials. Global settings.

 

Under creation of materials, we’ll cover both bitmaps and procedural maps. Let’s start by making some definitions.

 

When I refer to the use of bitmaps, I’m talking about using photographs of textures that can be placed as the appearance of the material (diffuse), the relief (bump) or the opacity. A photograph can give an amazing feeling of realism to a scene, but they have a potential problem. When you apply a material with a bitmap over a surface, if the surface is bigger than the size of the photograph (which you will define by mapping the material on the object), the image will be repeated. There’s a big chance that the texture has some different lighting in a part of the image, or a specific detail that will be easily noticed if it gets repeated many times in the surface, and all this is captured in a view. This pattern makes perspectives look very amateur, and you should try to avoid this effect. It is quite clear when you apply grass on a surface. If you take a photograph of a patch of grass, it is quite likely that when the camera captures a big surface (an aerial view, or simply the whole foreground), you will notice the pattern (see image below). Not good. But if you make the map bigger in order to have less repetition, you will probably miss the scale, and it will probably look worse than the pattern.

 

Your only solution in this case is to have a photograph of an area of grass that has been taken in similar conditions to the view you are going to render.

 

 

So what do we do in these cases? You can try to get seamless textures, or look for another solution in procedural maps.

And what are procedural maps? Procedural maps are created through algorithms, so they don’t have a beginning or an ending. That means that they won’t produce tiling at all. They can also be randomized, so you should not see a repetition that can cause the pattern to be detected in the scene (some may have a repetition, but should be unnoticeable if the mapping is done correctly).

 

Let’s see the same example I showed before, which now has a material composed of just green color, and a procedural map in the bump (will explain afterwards).

 

 

Rendering in AutoCAD part 1

Let’s cover rendering in AutoCAD.

The product has a very powerful rendering engine, which can produce photoreal renderings of your 3D models. Of course, if you are looking for the ultimate quality and power in rendering, it will be smarter to import the dwg into 3ds Max, but for a certain amount of users, AutoCAD’s quality may be enough, or may choose to only move to Max for the final renderings, and spend some more time visualizing the development of the design in AutoCAD. Remember, it’s never about one tool or the other, but about when to use a specific product.

 

I will divide this document in different parts, which will cover varied aspects of rendering in AutoCAD:

·     Creation and editing of materials

·     Creation and editing of lights

·     Creation and editing of cameras

·     Animations in AutoCAD

 

But first of all, I’d like to make sure that we are all in the same page on something: the purpose for rendering a still image or an animation is to communicate a concept. So you are actually telling a story, even if it is only an image.

 

For example, a camera targeting a building from the ground level, looking up, and with a very wide angle (first image below), will convey a sense of drama and scale very different to the same building captured from a bigger distance and with a narrow angle (second image below), which will almost produce no deformations at all. But the latter may be better to explain a master plan, or the position of the building in a specific context.

 

 

 

 

 

The use of a wide angle in a room will make it look bigger. There are many of these tricks that probably any photographer or film director know, and they are really important for you to understand. It is always a good idea to check photographs that you like, and try to understand which type of camera was used, understand the lighting, how you can introduce an object in the scene without really showing it.

I hope this is getting interesting.

 

There will be several postings about this topic, so stay tuned!

Rendering in AutoCAD... why not?

Now that we are making amazing 3D in AutoCAD, we may need to visualize it. 3ds Max is probably the best solution with the most efficient interoperability with AutoCAD, but did you ever realize the potential for rendering inside AutoCAD?

In following posts, I'll be explaining settings for materials, lights, animations and for the whole Mental Ray engine. I'll also cover interoperability with 3ds Max.

Just as an introduction, I would like to share a model I did in AutoCAD, and then rendered in AutoCAD too. I'll use it as an example of many different settings.

This is what the model looks like in the viewport. A bathroom is a great excuse for using highly reflective materials, which generally make everything look great! But normally the key to a great scene is an appropriate lighting. Light will help you tell a story, and this IS the most important thing in a still or an animation... what are you trying to communicate.

 

And this is the model after a render in AutoCAD. In Presentation mode, with all the settings done for real high quality, it took around 30 minutes. However, the one you see right now took around 6 minutes. The difference between the extreme high quality and the one you see (which I don't think it's bad at all), may be quite subtle, and you may not always need every option in the maximum.

I'll try to explain which values give you a better result without losing your CPU for half an hour :-)

Stay tuned!