Modeling Nurbs Dog

ART 484 - Modeling a Nurbs Dog

This page is designed as a supplement to lectures. It is not intended to be a stand alone tutorial.

Model Sheet
There are a number of methods of bringing in images to model from. In this example, we are using a model sheet, where numerous images of a figure or object are on the same sheet. When preparing a model sheet its helpful to have the images the same size and aligned for different views. This helps prevent one image being large than others in the different perspective or ortho views. This model sheet is available in bailey's pub space: /afs/umbc.edu/depts/vart/pub/bailey/maya/projects/classdemos/sourceimages. A Maya scene file of the model sheet setup correctly in the view space is available in the same projects directory.

Modeling Steps and Procedures:

In this exercise,we will not be attaching or using procedures to blend or fillet the legs onto the body. The 4 legs will just be "stuck" into the body as separate objects. An appearance of the legs blending into the body will be created by manually and carefully adjusting the CVs on the legs to match the curvature of the body.

In the Window that has the profile view, draw a nurbs curve on the front edge of the rear leg. Duplicate this curve and move the CVs until they match the back edge. By duplicating the curve, you are assured you have the same number of CVs in each curve. This makes for clean surfaces.

Duplicate the curve again and position it in the center of the leg. Change your view to the Rear and move the CVs of this curve until they match the outside of the leg.

Finally, duplicate the curve a 3rd time and create the inside of the leg.

Turn the Visibility of the Model Sheet off and you should have 4 curves that look something like this. Starting with the inside curve, select the curves in order around the leg and loft a surface. The first curve you select is where the seam would be and it would be smart to have the seam hidden.

Now you can start modeling the leg. Do NOT however, model the surface CVs. Instead, adjust the CVs on the curves. The surface will update with History turned on.

Keep checking the leg with and without the model sheets visible. Work it until you are close to something that you like. With just 4 curves, this makes overall modeling easy and quick.

An easy way to select curves and not the surface is to work in two windows. One that shows the surface and the other that only shows the curves.

When the overall shape is good, loft a surface that has 1 span between each curve. This will give you a surface with 8 vertical isoparms. Select the 8 vertical isoparms (as shown) and duplicate them into curves.

You can now delete the surface and you are left with 8 curves.

Using these 8 curves, loft a new surface and continue to model in more detail. Again, adjust the CVs on the curves and not the surface. In this step you can begin to get more detail on tendons, muscles, toes, etc.

When you have the leg as you want, delete the original 8 curves and you are left with a finished leg.

Sometimes having two mirrored legs makes it easier to see how the finished leg should look.

Repeat the above process to create the front leg

Repeat the process to create the body. In this exercise you will not model a head. Leave a circular hole for the tail. Work with just 4 curves at first (top, bottom, left and right). Then, as you did with the legs, create 8 curves from the surface, re loft and add in detail.

It is helpful to make the legs visible at time, as well as the modeling sheets. Pay attention to the upper part of the legs and adjust the body to begin to match the legs.

When finished you will have a form that is close, but the legs will not be blending into the body.

Wrangle the CVs of the legs until the leg appears to blend into the body. Take advantage of "pick walking" of CVs. Remember you can pick Hulls to select a whole group of CVs.

When you have one leg correct, simply duplicate to create the other.

You will extrude the tail. Select the isoparm around the tail hole and duplicate it into a curve. Draw a curve that matches the curvature on the tail as indicated on the model sheet. Extrude the circle down the path. Add in a scale factor to taper the tail down to nothing.

Adjust CVs to make the tail look like really grows out of the body.

Once the tail is complete, you can ATTACH the tail to the body - making one surface for the body and tail

In the Window that has the profile view, draw a nurbs curve on the front edge of the rear leg. Duplicate this curve and move the CVs until they match the back edge. By duplicating the curve, you are assured you have the same number of CVs in each curve. This makes for clean surfaces. Duplicate the curve again and position it in the center of the leg. Change your view to the Rear and move the CVs of this curve until they match the outside of the leg. Finally, duplicate the curve a 3rd time and create the inside of the leg.
Turn the Visibility of the Model Sheet off and you should have 4 curves that look something like this. Starting with the inside curve, select the curves in order around the leg and loft a surface. The first curve you select is where the seam would be and it would be smart to have the seam hidden.
Now you can start modeling the leg. Do NOT however, model the surface CVs. Instead, adjust the CVs on the curves. The surface will update with History turned on. Keep checking the leg with and without the model sheets visible. Work it until you are close to something that you like. With just 4 curves, this makes overall modeling easy and quick. An easy way to select curves and not the surface is to work in two windows. One that shows the surface and the other that only shows the curves.
When the overall shape is good, loft a surface that has 1 span between each curve. This will give you a surface with 8 vertical isoparms. Select the 8 vertical isoparms (as shown) and duplicate them into curves. You can now delete the surface and you are left with 8 curves.
Using these 8 curves, loft a new surface and continue to model in more detail. Again, adjust the CVs on the curves and not the surface. In this step you can begin to get more detail on tendons, muscles, toes, etc.
When you have the leg as you want, delete the original 8 curves and you are left with a finished leg.
Sometimes having two mirrored legs makes it easier to see how the finished leg should look.
Repeat the above process to create the front leg
Repeat the process to create the body. In this exercise you will not model a head. Leave a circular hole for the tail. Work with just 4 curves at first (top, bottom, left and right). Then, as you did with the legs, create 8 curves from the surface, re loft and add in detail. It is helpful to make the legs visible at time, as well as the modeling sheets. Pay attention to the upper part of the legs and adjust the body to begin to match the legs.
When finished you will have a form that is close, but the legs will not be blending into the body.
Wrangle the CVs of the legs until the leg appears to blend into the body. Take advantage of "pick walking" of CVs. Remember you can pick Hulls to select a whole group of CVs. When you have one leg correct, simply duplicate to create the other.
You will extrude the tail. Select the isoparm around the tail hole and duplicate it into a curve. Draw a curve that matches the curvature on the tail as indicated on the model sheet. Extrude the circle down the path. Add in a scale factor to taper the tail down to nothing. Adjust CVs to make the tail look like really grows out of the body.
Once the tail is complete, you can ATTACH the tail to the body - making one surface for the body and tail