UVW mapping a 3d model can be either very easy or very difficult, depending on the complexity of the 3d model and the final purpose of the computer generated image. If you have basic knowledge of texturing you know that if you have a “box like” model you apply a uvw map modifier with a box gizmo, for a bowling ball a spherical gizmo and so on…
But what happens if a client sends you a sample of a wood texture and ask you to apply that on a furniture element? One way to do it is to use tilling, but in order to do it correctly (keep the real dimensions) you need to do quite a few calculations to see how many times that texture should be tiled horizontally and vertically.

Fortunately there is another way to do it by using “real world scale” and that is the process I will try to explain in the following tutorial.

Download the 3d model
Download the wood textures that you will apply on the model

Before you begin, make sure that you have set your units to centimeters (or the units that you usually work with, except “generic units”) As you will see, for this type of approach to uvw mapping, the units are very important.

The model that we will be working with, will be mapped with 2 different materials, so the first step is to select the polygons that will have one of the textures assigned to it and set an id like in the pictures bellow.

With the selection still active, click on “edit”, “select invert” and you will end up with the other polygons selected; under “set material id”, type “2” in order to assign a new id to the second material.

At this moment you have the material ids set, so whenever you need to select the polygons that correspond to a specific material just click on “select id” and type the number that corresponds to the desired material.

http://www.cgdigest.com/material-settings/uvwmap/uvw.rar

Open the material editor, and assign a material for each of the polygon selection sets of your model.
Select the material slot of the first material that you want to work with and apply a checker map in the diffuse slot.
Under “coordinates” rollout make sure you check “Use Real World Scale” and type in the desired dimensions of your texture (in this case 5cm x 5cm).

Now apply a uvw map modifier to the object, select “box” and check “real world map size”. As you can see, every square of the pattern has 2.5 x 2.5 centimeters (the checker map is 2×2 squares with 5×5cm dimensions)

At this point, you can replace the checker map (that was just a placeholder to understand better how real world scale uvw works) with a desired wood texture, in this case a red oak. The important thing is to know exactly the size of the photo sample. This one is 35×52 cm, so you just need to type this dimensions in under the “size” parameter of the texture.

Click the image to view a higher resolution picture

Since we have completed uvw mapping the first material on our model, we can start working on the other one. In the diffuse channel select the desired texture, check “use real world scale” and type the dimensions like you did for the previous one.

As you can see from the photo above, the grain of the texture of the second material is vertical and you probably want it to be horizontal. The first thing that may cross your mind would probably be to change the axis of the uvw gizmo from “z” to “x”. This is only partially correct because even if it places the new texture correctly, it messes up the old one.

What you need to do is to collapse the uvw mapping modifier, select the polygons that correspond to the material you need to tweak and with the selection active, add a new uvw mapping modifier. By keeping the selection active, the new uvw mapping material will affect only the selected polygons.
Click again on real world map size and change the axis from “z” to “x”.

Click the image to view a higher res rendering

That’s about it; if you need to add more materials, just repeat the last steps; collapse the stack, selected again the polygons that you want to correspond to a new material, and add a uvw mapping modifier with the new selection set active.

If you have any questions feel free to ask.

Photomontage renderings, if done right, can be a lot more appealing and realistic than standard architectural renderings.
The reason why this happens is that a real environment with dust, dirt, scratches and imperfections, by definition looks better than a computer generated one.

Furthermore, creating the entire scene in 3d can prove to be very time consuming, and if you are working in the architectural visualization business you know that deadlines are usually very tight and you can not afford to lose more time working on the environment than on the building.

Having said this, let’s start with the tutorial. Usually photomontages are used for exterior renderings, but in order to keep this tutorial as simple as it can be, I have chosen an interior environment.

Taking the photo
The most important thing when taking a photo that you will later use for camera match is to take as many accurate measurements as possible (you will need at least 5 reference points). Take a look at the photo below (click on it to view a higher resolution image)

As you can see, the dimensions are noted on all 3 axis (horizontal, longitudinal and vertical).

The next step is to bring the photo into 3ds max. Click on “views”, “viewport background”, or just click “alt+b” (shortcut for 3ds max 9).
Under background source, chose the image you need and select “match bitmap” under aspect ratio.

Tick “display background” and select “active only” (with the perspective viewport active).
Click the image to view a higher resolution one

Now it’s time to model some basic geometry that we will later match with the photo.
Make sure that under “units setup” in the preferences drop down menu the units are set to the same ones noted when you made the measurements (in this case, centimeters).

You don’t need to model anything fancy… just a set of planes with the same dimensions as some elements in your scene. You need a 90.5×45 cm plane for the table top, a 20×20.2 plane for the vase and another plane placed at a distance of 4.6 centimeters behind the table top for the wall.

At this point it’s time to match the points of our geometry with the ones from the photo.
With the perspective viewport activated go to “create”, “helpers”, “camera match”, “cam point”. With the snap toggle on, start creating cam points at the corners of the table top plane, and at the top corners of the plane for the vase.
Click the image to view a higher resolution one

Go to the “utilities tab” and click “camera match”. You will see the list with all the cam points you have created in the previous step.

Select cam point 01, and click “assign position”. Now click the top left corner of the table top on the background image. By doing this you will tell the software that the cam point 01 needs to be placed at the position you have indicated.
Repeat this step for all the cam points.
Click the image to view a higher resolution one

After having done this, click on “create camera”. If everything has been done correctly, this step will automatically generate a camera that matches the view of the photo.
If you place a 3d model on the 90.5×45 plane in your scene, it will appear to be on the table top when rendered.
Click the image to view a higher resolution one

General camera match advices
As I said at the beginning of the tutorial, camera match can help you create a photorealistic rendering in a shorter amount of time. However, it has a downside too; unlike a standard 3d rendering, you can not change the angle later, so it is better to take several photos of the environment and explain to the client that he needs to decide upon a view and he can not change his mind later.

Taking dimensions for an exterior photomontage can proof to be more difficult than in the example shown in this tutorial. Therefore it is good idea to have objects with standard dimensions in your photos (like lighting posts, traffic signs, etc.)

Bellow are 2 examples of photomontage renderings that I have done using this techniques (click on the images to view high resolution renderings).

A free 3d model of a bar stool, suitable for interior restaurant renderings, bars etc.

The model is available in 3d max version 9 and 3ds formats.

Download 3D Bar Stool Model

Bellow is a small list of things that I consider important when doing architectural visualization (or any other subject, as long as it is supposed to be a photorealistic rendering), and from what I see in the image galeries, a lot of people don’t seem to care about.

1)    Use chamfered edges, especially in close-ups
In real life there’s no such thing as “razor sharp” edges. Take a look at the objects around you and notice that every edge is more or less rounded. Although in the cad files provided by the architects you will never see this, keep it in mind when building the 3d model. Bellow are a few images that illustrate better what I’m trying to say.

(click on an image to view a higher resolution one)



Chamfered edges not only will make your 3d models look more real, but also may “catch” specular highlights which will give more depth to the rendering.

2)    Don’t use 100% black or 100% white colors.
The explanation for this is very simple. To “show” an object’s volume you need to have highlighted areas, shaded areas and mid tones. This is one of the first things that you learn at art school. If a material that is assigned to a 3d model has a 100% black color in the diffuse channel, there will be no visible difference between the mid tones and the shaded areas and it will make your model look flat. Same thing goes for 100% white objects, only this time there will be no significant difference between light areas and mid tones.

3)    Blur parameter from 1 to 0.1
By default, the blur parameter in the bitmap’s “coordinates” rollout is set to 1. This causes the textures to look blurred, especially if they are looked at from an angle. By setting this parameter to 0.1, will make the texture look sharper and therefore more real (it will also increase the rendering times though…)

4)    Always use area shadows.
If you are doing an exterior rendering, you need to control the sharpness of the shadow, depending on the time of the day. In the morning the shadow is very soft, and it gets sharper and sharper until mid-day; after that moment, it softens again until night.
Even at mid-day the shadow is not 100% sharp though so you still need to use area shadow, just adjust the parameter to make it less soft. The photo below has been taken at mid day; take a look at it to see how crisp/soft is the shadow.

Same goes for artificial lighting. Some fixtures cast a subtle shadow, while others (like spotlights) cast a sharper one, but again you should always use area shadows and adjust the parameters accordingly.

Hope these were helpful; feel free to add to the list if you wish.