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Glass Vase
By Realsoft

Model a Pottery Vase

Easy - Beginners tutorial

This tutorial starts with creating a simple revolve, then texturing the result into a realistic pot. We make use of the "Scope" handler to show how to clip an image onto a surface that is already textured. All project files and textures can be found in this zip file.

The Finished Pot

PART 1 - Modelling the pot

Start with a new project and select the front view, turn off perspective and reset the view.

Under the main toolbar, select Polygonal curve by clicking the down arrow next to curve, then polygonal curve. Leave all the options at their default settings - we want to draw an axis vertically that we can sweep our pot around. Start the curve at the lower middle of the view window; click once, then make another mouse click straight up the view and towards the top so the line is roughly vertical. (Holding the SHIFT key will keep your line vertical) If you keep clicking at this point the curve can be made more complicated - but all we need is an axis so we will accept the curve at this point by pressing the ACCEPT button in the toolbar (you can also right click and accept). This finishes the creation of the curve.

To simplify matters - it is always a good idea to name your objects. Under the select window, we can see that we have created a nurbs curve. By slowly double clicking the nurbs icon we can rename the object. Call it "Axis".

We now want to create the "Profile" of the pot. Think of this as a section through half of the pot that is "swept" around our axis. Firstly though, we must select out axis - make sure it is highlighted before continuing. Under our main creation tab again, select "Cubic curve" this time. (Polygonal curves have sharp edges - quadric and cubic curves are very smooth)

We are going to use the axis curve we created as a point to rotate about when we make our profile. To do this, we need to select "Rotate" under our toolbar - click the Pen option to see the different methods - select Rotate.

Starting at right hand side of our axis, click points from the base upwards to create a profile curve similar to the one shown. Each red point represents a mouse click. To get sharp edges in a nurbs curve, we need to put the points closer together. Hence the top has three closely grouped points. Note too that the curve draws both the outside, then goes inside the pot as well.

The shape of your pot profile

Do not worry too much about how accurately you place the points - you can edit them later. Notice too how you can see the creation of the revolve. When you have finished creating all the points, click the ACCEPT button again to finish creating the profile.

Rename our nurbs curve to "Profile". Notice now that our level structure has changed and we now have a mesh in the view. We created the mesh by rotating our profile curve about the axis. The two curves are now put "under" the mesh. Press the "+" icon next to the mesh to see the curves below. By editing these curves now will change the shape of our resultant mesh. Note that a mesh is a 3D surface - so when we render the image this is what we will see. Generally, curves by themselves are not rendered.

Rename the mesh to "Pot". Lets tweak the profile curve a bit. Select the profile curve, under the context sensitive toolbar a series of options are shown that we can do to this particular curve. Click the EDIT button and we will move some points around to create the shape we want.

If you click on any single point, the cursor changes to a cross. This means that you can now click on the point and move it around. Do this for each point until it looks roughly like the above image and has an even space between the inside and outside. You can now pan around the view and examine the pot you have created.

To get a better feel for the shape - turn on Open GL view to see the mesh better. You can also raytrace the view by pressing raytrace.

This is a good point to save your work. Under the File pull down menu, select "Save As". Select the appropriate directory by clicking the "..." button next to the name field and Save the file as Pot_Part1

Part 2

Texturing a model is about applying materials to an object to achieve a given "look and feel". These materials can be as simple as colors, or as complex as applying bumps, reflectivity, color and shine.

We can very simply drag and drop the standard "glass" material onto our pot to create a glass pot. Likewise, we can make it gold, plastic or chrome by using many of the standard materials.

But we want the pot to use an image. This image could be a drawing, a color or a photograph. We will map this image onto our pot using the "Cylindrical mapping" method. We have many methods to apply the image to a model - parallel being the most obvious - it projects the image onto the model in the size and aspect you set when applying the material. Cylindrical mapping works on the same principal - but it wraps the image around the cylinder walls - much like the word COKE is written around a can. We can wrap 1 image right around the object, or we can make it "Tile" around. If I wanted COKE to appear twice, I would make it tile 2 times around.

In this example we are going to map a simple strip of color around our pot to make it look real. To do this we need to make this "Strip" tile about the pot 10 times. Here's how we do it:

Load Pot_Part1 tutorial if its not already active. Select the TOP view. Drag the Pot object mesh from the select window and into the view. This maximizes the object in the view. (you can do this for any object including a camera)

We should now have a wireframe view of the object like this.

Lets go to the Materials tab: In the select window, select the Materials tab. Lets purge any unnecessary materials for this project - under the pull down menus, select Materials/Purge material Library. This deletes any UNUSED materials. If a material is being used, it is kept. This should delete all the materials as we have not assigned any yet.

By Right Clicking in the blank area inside the material window, should bring up our pop up menu. Select New/VSL material. This creates a new blank material for us to edit.

Select the new material and rename it (by slowly double clicking) to "Pot". Now quickly double click the material. This should bring up a new window called "Property Window Sync". This shows us all the selected objects properties. In this case, it shows us the properties for our material "Pot" which happens to be empty. Lets fix this by using one of the pull down wizards. Select "Texture Map" from the wizard pulldown, Add this by pressing the ADD button next to the wizard. This inserts a file requester. Lets grab our texture map image by clicking the "..." button. (Next to the SHOW button) Navigate to our Texture directory, and select "D_potside1.jpg"

Lets map this material to our pot - in our material window, right click on our "Pot" material and select Map/Cylinder. This activates our tool to cylindrically map our texture to our model. It automatically assigns our material to whatever object is selected in the select window. Which should be our Pot Mesh as it is the only object.

To create our cylindrical mapping, first click at the center of the mesh, then just outside of the mesh. The result cylinder should just encompass our pot at its widest point. Rotate the view and see the result. Click the "Side" view. It should look similar to this image.

Note that the cylinder mapping is shown dotted. It is also smaller than our pot. We need the cylinder mapping to be just a bit taller than our pot and just a bit wider. It should be the correct width as we can see in our TOP view that it is just larger. Lets size the mapping to fit the pot:

Go to the select window and examine what has happened to our structure. Our mesh has been dropped to a new level. Click the "+" icon next to the level to maximize its contents.

Note how the mapping is "level" vertically with the mesh. This mapping is now applied to anything inside this level - but nothing outside of it. Select the "Cylinder Mapping(Pot)". This selects just the mapping object. Lets use the handles of the object to position it correctly.

Put the mouse cursor over the blue line of the object handle - the cursor should change to a "Move" icon. Click the mouse on the blue line and move the object to just below our pot. This puts our object handle out of view. If needed, Pan the view so you can see the blue dot at the end of the object handles.

Now put the cursor on this blue dot at the bottom of our object handle - it should change to a pencil icon - this means we can scale the object about this axis. Click and drag down to scale our mapping object larger vertically. Keep modifying the object until the mapping is just larger than the pot. Note how the scaling or rotating of an object occurs about the handle, hence it scaled upward. If it was positioned in the center of the object, it would be scaled in both up and down directions.

Our mapping should look like this. Render the view to see the result. As you can see - we have applied our strip of color around the pot but it looks awfully dark ! Lets add some lights:

Go to "Lightsources" under the main toolbar add some "Point" lightsources: Select Point - and click on the view for the lights center point, then another click to define how far the light should go. Add 2 or 3 lights around the pot. Render the view to see your progress and move the lights if needed. (Check your top and side views for light positions - move the lights by moving mouse over them and dragging).

Above is the image that we have stretched around the pot. (We have applied it vertically) It is very narrow and this results in a very "blocky" looking render of the pot. What we can do is tile this image around the pot a number of times. We change this by editing the "Scale" parameter of our mapping object;

Select the Cylinder mapping object, and click the "Spec" tab in our "Property Window Sync". (Remember we brought this window up by quickly double clicking any object). In the Scale field are three numbers. "1 1 1". This means that the mapping is mapped once in each three directions (X Y Z). If we want our strip to be repeated 10 times around, we actually need to make it 1/10th of the times in the X axis. Which means we need to Punch in "0.1 1 1" There needs to be a space between each value as each value represents the X Y Z value. Try rendering the pot now and see what happens.

Our pot has only a strip of the image applied now ! This is not what we want - it should be TILING around the object. We set this parameter in the material itself. Go back to our material tab and select out Pot material. In our Property window, there is a checkbox for "TILE X". Turn this ON and render again. Much better ! We have now tiled the image around our pot 10 times.

Just for the sake of making our scene a little more interesting, lets add a ground plane. In this case, lets put a disk underneath the pot so we can see some shadows. Under our Creation tab, select "Analytical Disk" under the circle icon. In a Top view, click the center point first (Center of the pot) then another point further out, well away from the pot. In a side view, move the disk to just below the pot.

Save your work as Pot_Part2.

Part 3

We have created a very basic pot with a simple cylindrical texture applied. We will continue fine tuning our material here and also map on a "leaf" to the pot that shows some of the power of VSL.

Load "Pot_Part2". This scene has some lights and a ground applied to show off our pot better.

Lets continue to tweak our material and give the pot a few more realistic attributes.

Go to Materials tab in the select window and select our "Pot" material. Double click the material if the Property window is not already up.

Lets use another wizard and add some "Ping" to our pot, using the "Specular Color" wizard - Add it too.

Try rendering the view to see the difference. It renders as if it is made from gold. We want a more subtle appearance - so change the specular values to read:
Sharpness = 3.00
Brightness = 0.80

We could go on to add bump and a bit of reflection if we wanted - but lets get started on a new material to map a "leaf" onto the pot.

Create a new material - right click in select material window and select New/VSL material.

Rename the material "Leaf". (We can do this by changing the name in the Property window too)

We have two "modes" when creating materials - Basic and Advanced. We are currently looking at the Basic mode in our property window. If we tick the "Advanced" button at the top left we can see exactly whats going on in this material. Lets do this.

Use another Wizard and create a "Texture Map". This creates a new surface property that is assigned to a texture. This texture is, by default, assigned to the color channel of an object. But we want it to be assigned to the "Scope" attribute in this case. The scope channel controls how much of a material is shown and how much is not. This is a powerful function that allows us to put any image onto an already mapped object (or unmapped) and clip out any undesirable background so we have only the desired portion shown on the image.

This has applications in assigning text over a material and removing the background so we only see the text. Assigning a complex window bitmap over a brick mapped wall, mapping a logo to a product etc.

We "Cut" our image out to do this - generally with an alpha channel (Extra information in an image that stores "transparency" data - typically Targa files are saved with an Alpha channel) We could also use a specific color value to do the same effect - but we have a Targa file with an alpha channel already setup.

Select our new texture map icon that has been placed in the properties window (red paintbrush icon) At the bottom of our properties window we see a file requester window similar to the basic version we used previously. Select the texture "D_potleaf+A2.tga" by pressing the "..." button.

If we were to map this texture onto our pot now, it would overwrite the material we created previously, so we need to setup our "Scope" value so only where the leaf texture is shall me mapped onto our pot. Right click on the color=texture icon and select Copy, then Paste. This creates a duplicate of the texture we just assigned. Select the first texture map. Right click and under "Output >" select "surface : scope." This changes the output from the texture map to go to the scope instead of the color. But by default this is using the Red color channel to do this. We need to go to the "Bindings" tab and make the Alpha the channel to use:

Under the channel bindings we can see that currently, the scope is assigned to color:R. We need to change this. Check the "Edit Bindings" button at the bottom. This opens up more details as shown above. Select the Color:R -> Scope under channel bindings. Then Click the "Remove" button. Now select "Alpha" under the Image channels, and Scope in the Material channels. The Add button becomes active. Add. This now assigns the scope channel to the alpha from the image.

And that is the basic structure of our scope material. Lets assign this to our pot and see what all this complicated VSL does. Go back to the select window. Click the FRONT view and make our pot full screen (drag the mesh to the screen) Make sure that the pot LEVEL itself is selected and not the mesh as the material will but put inside this level. Go to the material tab again and select our "Leaf" material.

Right click on the material and select Map/Parallel. Draw a rectangle roughly square - starting click at the top left and 2nd click bottom right. The map object is now inserted under our level as shown above. We can select the mapping object and scale/reposition it as necessary.

Rendering the view should yield a result similar to this:

Make a few test renders around the object. Notice that we can move the leaf map around the object and it covers whatever is under it. But there is one small problem. The leaf appears on both sides of the pot ! It is by default, mapped straight through and will continue going on forever. If we set the tile X + Y buttons on, it would repeat over the object as well. In this case, we only want 1 copy of the leaf, so we will set some attributes under the mapping object:

Select parallelmapping(leaf). Under the "Spec" tab in the properties window are three toggles - select them all ON - "Finite X,Y,Z".

This limits the extent of our leaf material to within the boundaries of our mapping object. This is a very handy feature ! Modify our parallel mapping object so it sits within 1 side of our pot and looks similar to this:

Finally, lets add a bump map to our material to give it a realistic "raised brushstroke" feel.

Select the leaf material. Using a wizard, add a bump map. In the name field, select the "B_potleaf+A2.jpg". Under the Bump Height field, enter "-1".

Render your pot. Notice that all these materials have very subtle effects. To see what any of the parameters do - increase the values. (eg. change the bump height to -5)

To finish off our scene - lets change some of the values of the "Ground" object without assigning a material to it. Go to the select window and select the Ground object. Under the "Col" tab of the properties window are various surface properties that we can change without the need to assign a material to. (A material would over right these settings)

Right click on the white square. Only one options appears: "Expand". Click this. This brings up our color wheel. Select any color you like. Next to Attribute, Select the "Reflection" attribute. This uses a greyscale value to say how "Reflective" an object is. Black is none, white is mirror. Select a dark grey.

Your final scene should look like this.


Page updated on Tuesday, 25 February, 2003 . For feedback / model submissions or articles - please email us.
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