Polygon Texturing

This is a polygon-texturing tutorial for maya 5.0. In this tutorial, I am going to go through the steps it takes to layout UV's of a model, create the texture map, specular map, and displacement map. Texturing with lighting is one of the most overlooked areas in the 3d animation process. From my experience at SCAD, I have found that most students don't really understand texturing and very rarely is there a good texturing tutorial on the internet. It is a struggle for many people to understand. It is also one of the worst documented processes for Alias|Wavefront, no offense to them.

This is the stool that I am going to go through. I picked this model because it's not completely rigid, and it's not too organic at the same time. This model also gives the opportunity to show several techniques to the texturing process. This model is also not super high in polygons, but it's not quite a low-poly model either.

This final rendered image does include specular, and displacement maps to the stool. I am going to go through and explain what all three maps do, and how to apply them to your model.

If you want to go through the process with me, I have the original file of the stool available.

Follow these steps to get the file:

  • save this link
  • copy the text from the txt document, and paste it into a blank txt file.
  • change the extension on the end from .txt to .ma
  • voila, you have your maya ascii file of the stool

Once you have opened your scene file of the the stool, go up to the top left corner and be sure you're in Modeling mode before we start.

Next in the main menu go to Window, and under the window select the UV Texture Editor...

You will notice a window pop up that looks like this. This is the maya UV Texture Editor. If you plan on becoming a texture artist of some sort you will become very familiar with this window and it will become your best friend.

Most other 3d software packages have something very similar. In maya 5.0 they made the buttons at the top accessible at a GUI level. Some of them were available in 4.5 but now you can see them as buttons, and Alias|Wavefront added some new buttons.

Have both the stool, and the UV Editor in view.

Now select the stool. Notice how when you select the stool, you see a tangle of polygons show up in the uv editor. This tangled mess that you see are the uv's for the stool. And we're going to untangle it! Before you decide to quit this tutorial, you should know that maya has some useful tools to "unwrap" this mess.

UV's should actually be called st points, but maya decided to give them another name. So I will refer to them as uv's. They are points that correspond to the vertex point on the model. You can think of the uv's as vertex points within 2d space rather than being in a 3d space.

Be sure the entire stool is selected. You can select one part of the stool, then keep hitting the up arrow until the entire stool is green. This means you are going up through hierarchy of the model to its group leve.
Now hit F8. This will bring you into component mode. We will want to select the faces so put your curser over the stool and hold your right mouse button down. You will see a group of options appear. Select "Face"

In the front view select the top and bottom of the seat. Here are some selection tips for maya:

click + ctrl + shift = add to selection

click + ctrl = deselect from current selection

click + shift = reverse current selection mode

 
Go ahead and scale the circles down so they're a little smaller. So that they fit in the bottom corner fo the second quadrant.

Notice how the top and bottom of our seat are literally projected ontop of one another. This is totally fine, acceptable, and encouraged. Overlapping uv's can save resolution space, and eventually make up for a higher detailed model

A window pops up. These are the options for the planar projections. In the Mapping Direction, be sure to select camera. This way, we can create projections from our current camera view, instead of trying to project to a specific axis.

Click on Apply then Close

If you closed the uv texture editor open it. If you already have it open, you'll notice that the top and bottom of the seat were projected from our top view. This means that the uv's for the top and bottom of the seat are now layed out becuase of the planar projection.

This next step is very important, and if not done, can cause alot of confusion within the uv texture editor

You will notice that there are some handle tools around the object. These are the inital tools brought up right after a projection. The squares are for scaling, the arrows are for translating, and the blue arc is for rotating

Click and drag the selection to the second quadrant on the left.

Now scale it smaller, so it fits easily into the second quadrant. It doesn't have to be a perfect circle, just eye it

Now click anywhere within the uv space. You will notice that our projection has become deselected, and you can see the rest of the uv's in the first quadrant.

Something important to remember when moving selected uv's within the uv editor: Just because you can't see the uv's, doesn't mean they're not there, as we just witnessed. That is why it was important to move our selection into the second quadrant. This way we can work with our projected uv's without getting them confused with the rest of the uv's. Feel free to use the open space outside of the quadrants to temporarily place layed out uv's. Just don't forget where you left them

You can still edit the uv's if you want. Put your cursor somewhere within the uv editor and hold down your right mouse button. Select UV.
Now if you click where the lines are connected you can select individual uv's. You can also scale, translate, and rotate them like vertex points with the keys: w, e, r

Go ahead and scale the circles down so they're a little smaller. So that they fit in the bottom corner fo the second quadrant.

Notice how the top and bottom of our seat are literally projected ontop of one another. This is totally fine, acceptable, and encouraged. Overlapping uv's can save resolution space, and eventually make up for a higher detailed model

Now that we have the projection for the top and bottom of the sead finished, we're going to project the side of the seat.

Switch to component mode, and your selection mode to Face. Select the side of the seat.

Another easy way to select the side of the seat is to select the entire seat, then deselect the faces of the top and bottom from the uv texture editor. This will leave you with just the side selected



Notice how with the top and bottom of the seat we used the planar projection. This type of projection will not work for the side because it curves around. So for this case we will use a cylindrical projection.

From the menu under Edit Polygons, Texture, select Cylindrical Mapping



If you look in the uv texture editor, you will see that the uv's for the side are now projected and layed out



Just like the top and bottom of the seat, move the side of the seat to the third quadrant. And scale it so it fits well into the quadrant

After scaling the side of the seat, go ahead and move it into the second quadrant with the top and bottom of the seat.
Select the side of the seat, and move it just over the circles. But not too close if you want to select them again to move them in the future.

Texturing tip: If you want good textures, it is important for your uv's to be consistent in size. For this example, the side of the seat has to be close to the same size as the top and bottom of the seat. In other words, if you were to wrap the side around the circle it should be long enough to wrap all the way around. You may have to stretch the length of the side piece. This will keep the texture looking consistent among the whole model.

Now that the seat is layed out, we're going to move on to the legs of the stool. Go back to object mode by hitting F8 on your keyboard. Select one of the legs of the stool.

Hit F8 again to go to component mode, and switch to the Face option and select the entire leg.



Just like the side of the seat, select the Cylindrical Mapping option.

For the most, this does the trick but there needs to be some tweeking with cylindrical tool.


Notice at the bottom of the cylindrical tools there is a red "T" shaped tool.

Click on the bottom of the red "T".

If you look in the uv texture editor, you will see that the uv's for the side are now projected and layed out

Notice that at the center of the cylinder tool there is a blue circle that shows up.

Click on the blue circle.

Notice now that you have all of your rotation tools available. Rotate the cylindrical projection so that it is parallel to the leg. If you are doing this as you look at the uv texture editor, you will see a real-time change in the projection. The goal is to get a uniform box of squares for the projection. This will ensure the least amount of stretching for your textures.

Doing this and getting it right takes quite a bit of practice and time. Don't get frustrated if you can't seem to get it to look just like this image

Once you think you have the projection where you want it, move it down to the third quadrant of the texture editor.

This is a very important step. Because if we didn't move the leg projection, and we deselected it, it would be sitting right ontop of the mess of other uv's that have yet to be projected. Then it would be hard to see what to select. Of course it is still possible to select just the leg by doing so in the openGL window.

Remember, just because we can't see our seat doesn't mean that it isn't there. It's still in the second quadrant. We can't see it just because it's not selected. Keep that in mind when moving other projections.



If you were to select both the leg and the seat, then you would see both of them in the texture editor like this.



Go ahead and scale the leg, and move it into the second quadrant with the seat.

Remember what I said earlier about keeping the scale of the projections consistent with each other. Because the leg is long and skinny, I squashed it so that ideally it would wrap around in the right size. This doesn't have to be perfect or even accurate. But do your best to eye it according to the size of the other objects.

Go ahead and do the same steps for the other two legs, using the cylindrical mapping tool.

Because all three of the legs look the same, you can put all three projections right ontop of each other, just like we did for the top and bottom of the seats. This will give us more detail to our texture later on.

Now if you should have all three of your legs projected and layed out. If you select all three legs, and the seat, your uv editor in the second quadrant should look something similar to this.

I haven't mentioned it before, but now is a good time to mention seams. Because we are unwrapping these cylinders, unlike a circle, there has to be a starting edge and an ending edge. However when they are wrapped together, there is no edge. For texturing this creates a problem, and often you will see models with a seam running down the arm of a character. To keep this tutorial simple, I won't get into the detail of how to eliminate seams, but I hope to cover this topic in another section of my webpage in the future.

Now we're going to layout the uv's of the horizontal beams.

Go to the object mode (the green one) if you're not already in it, by hitting F8.

Select one of the beams.

Go to the component mode by hitting F8 again.

Put your cursor over the beam and hold your right mouse button down. Select Face.

Now click and drag over the entire joist.

Just like the legs, we're going to do a cylindrical projection onto the beam.

With the beam selected, under the main menu, Edit Polygon, Texture, select Cylindrical Mapping. If you have the uv texture editor open, the projection will look like this.



Select the red "T" shaped tool at the bottom corner of the cylinder. Notice how the blue circle appears.

Click on the blue circle



This will give you all of the available rotation tools.

Rotate the cylinder so that it is parallel with the beam. It also helps to look in the uv editor. Again, the more straight the faces are, the less room for distortion.

 
Remember to move the uv's off of the first quadrant before you deselect them

Hit F8 to go back to object mode.

Select the entire stool to show all of the uv's.

Once you can see all of the uv's move the uv's of the beam up into the second quadrant with the rest of the layed out uv's.
Do the same process for the other two beams. You can put the uv's of the beams all ontop of each other, just like I did for the legs.

The only thing left are the small wooden rivets on the legs.

In object mode, select all 6 of the rivets.

Because the rivets are so small, the seams will be almost un-noticable. So for this, we are going to use the Automatic Mapping tool.

With all of the rivets selected, under Edit Polygons, Texutre, select Automatic Mapping.



Maya arranges the uv's so that they are layed flat out, so when a texture is applied, they won't stretch the texture.



Scale the uv's of the rivets down so they fit in the second quadrant with the rest of the uv's.

Remember if you can't see the other uv's, that is because they're not selected.

Now that all of the uv's for our stool are layed out, select all of the uv's and move them back into the first quadrant.

Now we are going to make a snapshot of these uv's so we can paint over them in a painting package such as Photoshop.

Be sure all of the uv's are highlighted.

In the uv texture editor, under Polygon, select UV Snapshot...

A window will pop up for the UV Snapshot. Here you can set the resolution for the image, file type, and where you want it saved.

So under File Name, select the directory you want to save it in.

For Size X, Size Y, I typically set my snapshots to 1024 X 1024. Maya has a hard time dealing with maps higher than 3000. Don't try it.

For Image Format, I usually use Tiffs.

Once everything is set, click on the OK button. It takes a couple seconds for Maya to take the snapshot. But now we have an image of our uv's!

Before we start working on our texture maps, I usually delete the history on the model. This deletes all of the uv translation, projection, and rotation nodes. It also makes the model file smaller.



This is what the snapshot of the uv's look like in an image viewer



I typically work in Photoshop, and occasionally Deep Paint. If you're working in Photoshop, this will be useful for you.

Copy another layer of the uv's, and set it to Screen.

Then create a new layer between the two uv layers. This middle layer is where I paint my texture map. With the top layer set to screen you will be able to see the uv's and still work on the middle layer.


This is what my texture map looks like as I have been working with it in Photoshop. It is important to remember what uv's are what for painting your images.

For my texture maps, I use photo reference to paint my images. Cheating is good when creating texture maps. It also depends on the style that you are going for.

For my maps, I will usually paint over the images to touch them up and really make them distinguishable.

This is the specular map. The specular map will tell the renderer what part of the map should have a matte reflection, and what part has a glossy reflection. The areas that are white are glossy, and the areas that are black are matte. This gives the user control in where they want their object to show highlights.

To create this image I make a greyscale image of my texture map, and bump up the contrast.



This is the displacement map. This is what really gives life to the object. Like the specular map, the renderer uses the displacement map not to change the reflectiveness, but the height of the geometry. The renderer reads white as 1 and black as 0. The reason the image is blurred is so that the changes in shape will be gradual.

This is done simply taking the specular map, and throwing a gaussian blur on the image.



Now that our maps are created, I am going to go through steps it takes to create the shader for the stool.

Back in maya under Window, Rendering Editors, select Hypershade...

This will open a window called the Hypershade. The hypershade is a tool for creating maya shaders.

Click under Create, Materials, Blinn. This will create your blinn shader. I prefer the blinn shader over the lambert because it gives me the option of controlling the specularity.

Double click on the blinn shader.

Up at the top where it says "blinn:" type stool into the field.

Under Common Material Attributes select the box for the Color

This will open another window that allows you to select the node type.

Select the File button.

This will bring you back to the attributes of the stool shader.

change the file field to "stool_TXR". This just keeps the nodes organized, so you can recognize which node is for what type of file.

Select under File Attributes the location of the texture map file beside "Image Name:"

Now the texture map is applied to the shader.

Go back to the main attributes tab by clicking on the stool tab.

Under Specular Shading click on the button for the Specular Color.

The Create Render Node window pops up again. Just like the texture map, select the File node.

Under the file field type "stool_SPEC"

Now under the File Attributes, link the "Image Name:" to the location of your specular map.

Now the specular map is linked in our shader.

Go back to the main stool tab. Now we are going to link the displacment map to our shader. This, for some reason is a difficult node to find within the Attribute editor.

Click on this button where I've circled here in pink.

Now click by Displacement Mat. where I've circled here in blue.

Just like the texture and specular map, select the File node

You will see two tabs at the top. Click on the second tab labelled: file 1

Just like the other maps, name this file node: stool_DSPL

Also link the displacment map.

If you notice in the hypershade, unlike the nodes for the texture and specular map, maya adds the displacment node icon with the hypershade.

Now the stool shader is complete with texture, specular and displacment maps.

Select the entire stool

Next, in the hypershade, put your cursor over the stool shader and hold down your right mouse button.

Select: Assign Material To Selection

Voila. The stool is finally textured

Now that you can actually see the texture on the object, you can go back into the uv texture editor, and tweek the uv's so that they fit on the object better.

Now you have gone through the entire process for texturing a simple poly-object model. Don't you feel a sense of accomplishment?!

If you have any questions don't hesitate to e-mail me.

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