This article by Allan Brito guides you through the first steps of the modeling by using concept drawings to create a base model in Blender. The base model is very important to add details and upgrade the first flat surfaces into something more complex. This article tells us how to set up and configure a background image, and how to model and transform a mesh by using the background image as a guide. It also demonstrates the use of various tools such as Edge Loop tool, Face Loop Cut tool, and 3D Cursor as a tool.

With the base model created, we will be able to analyze the shape of our model and evaluate the next steps of the project. We can even decide to make changes to the project because new ideas may appear when we see the object in 3D rather than in 2D.

Starting with a background image

The first step to start the modeling is to add the reference image as the background of the Blender 3D view. To do that, we can go to the View menu in the 3D view and choose Background Image. The background image in Blender appears only when we are at an orthogonal or Camera view.

The background image is a simple black and white drawing of the weapon, but it will be a great reference for modeling.

Before we go any further, it's important to point out a few things about the Background Image menu. We can make some adjustments to the image if it doesn't fit our Blender view:

• Use: With this button turned on, we will use the image as a background. If you want to hide the image, just turn it off and the image will disappear.
• Blend: The blend slider will control the transparency of the image. If you feel that the image is actually blocking your view of the whole model, making it a bit transparent may help.
• Size: As the name says, we can control the scale of the image.
• X and Y offset: With this option, we will be able to move the image in the X or Y axis to place it in a specific location.

After clicking on the Use button, just hit the load button and choose the image to be used as a reference. Since you don't have the image used in this example, visit the Packt web site and download the project files from Support.

If you've never used a reference image in Blender, it is important to note that the reference images appear only in 3D view when we are using the orthographic view or the camera view mode. It works only in the top, right, left, front, and other orthographic views. If you hit 5 and change the view to perspective, the image will disappear. By using the middle mouse button or the scroll to rotate the view, the image disappears. However, it's still there and we can see the image again by changing the view to an orthogonal or camera view.

Make the image more transparent by using the Blend control. It will help in focusing on the model instead of the image. A value of 0.25 will be enough to help in the modeling without causing confusion.

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Using subdivision to model

With the reference image placed in 3D view, we can start modeling. This next part of the article will seem a bit repetitive, but it will use a common technique for polygon modeling, which is the adjustment of the model to the lines of the reference image. If you have already worked with this kind of modeling, it won't be hard to follow. What if I've never done that before? Well, in this case, let's learn how to handle a modeling like this one.

The first step is to create a cube, or use the default cube of Blender. To create objects in Blender, we can either press the Space bar or use the Add menu. All of the objects are created at the same position of the 3D cursor, which is the little target we see in the 3D view. This cursor can be moved by right-clicking at any point in the 3D view.

Before we go any further, let's take a moment to analyze the work modes in Blender. Some of the work modes in Blender are object mode, edit mode, and sculpt mode. For the modeling part of this project, we will mostly be using object mode and edit mode. Let's take a look at the differences between these two modes:

• Object mode: This is a mode in which we can select and manipulate the objects completely. The object mode is the best work mode in which to make object transformations, such as move, scale, and rotate. In object mode, we can't select the sub-parts of the 3D model like vertices, edges, and faces. As this type doesn't allow us to change the vertices, edges, and faces of an object, it's the safest way to make transformations without accidentally deforming the object.
• Edit mode: In edit mode, we will be able to select and change the vertices, edges, and faces of an object, which is why we will always use this type of work mode to apply changes to objects.

There are two ways to change the work mode between object and edit in Blender 3D, which involves the use of the Tab key or the work mode selector, placed in the header of the 3D view. This selector is placed below the 3D view right next to the text menu options in the header.

To use work modes in Blender properly, follow these two simple rules:

1. All of the objects should be created only in object mode. If an object is created in edit mode, it will be added to the object that is already being edited. It would be something like adding the geometry to the object, and at the end, we will have a compound shape formed by a lot of different objects.
2. Right after the creation of an object, check to see if the work mode didn't change to edit mode. In the past versions of Blender, the swapping to edit mode always took place when an object was created. In the latest version, however, it remains in object mode by default; still, it's always a good idea to check it to avoid problems with the modeling.

Select this cube, and with the scale, change the size of the cube until it fits the area pointed in the following image:

Another way to start the project is with a simple mesh plane. A few artists prefer to use a plane to model because it's easier to control and has fewer vertices to manipulate. With a plane, we would have to create half of the object and create a mirrored copy with the mirror modifier at the end of the modeling.

If you don't remember how to do that, just use the S key to scale the object. Additionally, to make a scale in a specific axis, use the X and Y keys to constrain the scale to the X and Y axis.

Now it's time for our first extrusion! Select the vertices pointed in the image below using the B key to make a border selection. Make sure you are in with wireframe as your dram mode. If you are not in wireframe mode when the selection is made, your vertices at the back of the model won't be selected.

There is an option called Occlude background geometry that is turned on by default. If you want to work on shade view, make sure this option is always turned on. Otherwise, you will have some troubles with the selection of objects occluded by faces near the camera.

Some useful keyboard shortcuts for this type of modeling:
To change the work mode use the Tab key. The selection mode can be switched with the Ctrl+Tab keys, and the transformation widget can be turned on and off with the Ctrl+Space keys.

With the view mode switched to wireframe, select the vertices pointed in the following image and extrude them with the E key:

If anything goes wrong with the extrusion, we can press the Esc key to cancel the operation. If the extrude has already created some geometry, the Esc key will cancel the operation but it won't erase the new faces. In this case, it's always good to use the Ctrl+Z keys to undo the extrusion.

The extrusion will be used again to create more geometry for the base model. This time, select the vertices at the bottom, and make two extrusions to the lower part of the object. Right after pressing the E key to extrude the selected vertices, press the X, Y or Z keys to constrain the extrusion to one of those axes.

After the last extrusion is created, remove all of the selected vertices and select only the vertices pointed in the following image. These vertices will be moved just a bit to the right.

A different way to model the object is by switching between the selection modes from time to time. For instance, when we have to select a set of faces formed by 12 vertices, sometimes it's better and faster to select everything in face mode. Just change the selection mode with the Ctrl+Tab keys and right-click on each face while holding down the Shift key.

Working with polygons requires a great deal of knowledge to place and manipulate the edges of a model. Sometimes, we will have to add or remove new edges to be able to work with it. For instance, we have to add an extra loop to our model; otherwise, we won't be able to create another extrusion in the right place.

In Blender , these new loops can be added with the Face Loop Cut tool. Make sure that you are still in edit mode and press the Ctrl+R keys. It will add a magenta line to the model, where you should choose the position and orientation of the new edge loops. Place the new loops in a way that it stays aligned with the guideline of the reference image, pointed in the following image:

With the new edge loop created, we can carry on with the modeling. Select the top vertices on the right of the model, as shown in the following image. We will create a set of sequential extrusions that will end up in a model like the one in the next three images. In the third image, we will have to select the upper vertices and move them to the right.

Make sure that you use the B key and draw a selection window to add all of the vertices to the extrusion.

Or, change the select mode to face to right-click on each face of the mode. This action, however, would require a small rotation on the view.

Here, we encounter the same problem. We need an extra cut to keep the extrusions. So, use the Ctrl+R keys to add an extra loop, as shown in the following image:

Modeling, rendering, and animating realistic machines with Blender 3D Walk through the complete process of building amazing machines Model and create mechanical models and vehicles with detailed designs Add advanced global illumination options to the renders created in Blender 3D using YafaRay and LuxRender Create machines such as a handgun, a steam punk spacecraft, and a transforming robot  http://www.packtpub.com/blender-3d-2-49-incredible-machines/book

The next step would be to select the vertices of the model and carry out another extrusion. But, in this case, we have to work on a small problem. The faces of the model are not orthogonal with the guidelines. When we press the E key, it won't be aligned. To solve that, we have two options:

1. Create all of the extrusions first, and after all of the geometry is created, move the vertices of the model to align it with the guidelines.
2. Use a trick to extrude the faces and cancel the transformation right after the creation of the faces.

For this case, we will use a trick. It's quite simple to use; simply select the vertices and extrude them normally. Right after the extrusion, without clicking the mouse, press the Esc key to quit the transformation of the new vertices. When we press the Esc key, all transformations, such as move, rotate, and scale will be canceled, but the geometry created with the extrude will still be there overlapping the selected objects. Immediately after the Esc key is pressed, press the G key and move the new vertices. If you want to constrain the motion the vertices in the X or Y axis, press the X or Y keys once when you are moving the vertices. It's quite important that you press the G key after the cancellation of the transformation because the new geometry created with the extrusion will be automatically selected.

Let's continue modeling with the selection of the vertices circled in the following image:

The extrusion of these vertices will create a new part of our model but, again, we face a small problem. The problem is that the new faces are completely out of alignment. If we follow the extrusions the way they are, the alignment will need to be made by hand, which is not very good. By the end of the modeling, we will certainly have some troubles with the edge loops.

So, here is the trick! Select all of the faces that you want to align in the same plane. When all of the vertices are selected, press the S key to scale all of the faces. While you are still scaling down the vertices, press the key corresponding to the perpendicular axis for the planes of the vertices. In this example, I will press the Y key once.

After pressing the Y key, press the 0 key once on your keyboard. This will set the scale size to zero and will flatten out the distance between all of the vertices.

Here is the result of the use of the trick in our example:

It will be quite easy to move the aligned vertices a bit to the right and then extrude the planes a few times—to be more exact, seven times. Use the lines of the reference image as a guide.

The right side of the model has a lot of non-orthogonal lines and planes, and to model those parts, we will use a simple move transformation. Select the vertices pointed in the following image, and move them to the right. To finish these last adjustments, select the vertices pointed in the image on the right, and move them until they get aligned with the lines of the reference image. For this type of action, everything must be done by eye, without the aid of a specialized tool.

The next step is to work on the connections on the top of the model. We can rotate the view of the model for a better view by using the scroll or middle mouse button. By doing that, the background image will disappear, but it's only because we left an orthogonal view.

To make those connections, we will use a tool in Blender called Skin Faces/Edge-Loops. This tool connects two selected faces and makes the required faces and edges connect automatically.

If you want to make this part of the editing process easier, change the select mode to faces and select, with a single right-click of the mouse, the faces pointed in the following image. When the faces are selected, press the F key and choose Skin Faces/Edge-Loops.

By doing that, we will be creating new faces and edges required to connect the faces. It's quite simple and a handy way to create new geometry. With the same tool, select and repeat the process for the other three required connections until our model looks like the following image:

With this last editing, we can leave the top front of the model and turn our attention to the back. Now it's time to work on the hand wrap of the gun.

>> Continue Reading: Polygon Modeling of a Handgun using Blender 3D 2.49: Part2

If you have read this article you may be interested to view :

• Polygon Modeling of a Handgun using Blender 3D 2.49: Part 2
• Modeling a Steampunk Spacecraft using Blender 3D 2.49
• Make Spacecraft Fly and Shoot with Special Effects using Blender 3D 2.49
• Character Head Modeling in Blender: Part 1
• Character Head Modeling in Blender: Part 2
• Creating Convincing Images with Blender Internal Renderer-part1
• Creating Convincing Images with Blender Internal Renderer-part2

Modeling, rendering, and animating realistic machines with Blender 3D Walk through the complete process of building amazing machines Model and create mechanical models and vehicles with detailed designs Add advanced global illumination options to the renders created in Blender 3D using YafaRay and LuxRender Create machines such as a handgun, a steam punk spacecraft, and a transforming robot  http://www.packtpub.com/blender-3d-2-49-incredible-machines/book

About the Author

Allan Brito is a Brazilian architect specialized in information visualization. He lives and works in Recife, Brazil. He works with Blender 3D to produce animations and still images for visualization and instructional material. Besides his work with Blender as an artist, he also has a large experience in teaching and researching about 3D modeling, animation, and multimedia.

He is an active member of the community of Blender users, writing about Blender 3D and its development for websites in Brazilian Portuguese(http://www.allanbrito.com) and English (http://www.blendernation.com).

This is his third book on Blender 3D, the first one was Blender 3D—Guia do Usuário, which was published in Brazil. It's a guide on how to use Blender that covers everything from the basics to character animation. The second book, Blender 3D: Architecture, Buildings, and Scenery, covers the use of Blender for architectural visualization. It is written in English, and is published by Packt Publishing.

He can be reached at his website, http://www.blender3darchitect.com, where he covers the use of Blender 3D and other tools for architectural visualization..