Eye with XSI


By David Alonso


Basic tutorial, made for version 1,5 of later XSI or. The first part is oriented to learn to generate textures using the possibilities of the Render Tree and the second sample some of the tools of the XSI that will allow us to automate animation controls.

PART 0: Before beginning

A general recommendation at the time of considering any project made in 3d is to have a clear idea of which we want to get to do. Always, until in smallest of the projects he is useful to look for more information, coverall visual references, images, videos, that contain great amount of useful data. For example, in this tutorial which we want to do is an eye, everybody knows that it is an eye and that aspect has, but in a photography, or a graph contains much more information than our memory: on proportions, forms, textures, whatever shine a material or whereupon reflected intensity.



In order to develop a model 3d of an eye to use it in a personage, we will not need to reproduce all its internal structure, but to know it will be to us of utility at the time of reproducing its form to act.

PART 1: Textures for an eye

First that we are going to do it is to model two spheres so that they have the appearance of an eye. It generates a sphere NURB (get > primitive > surface > sphere), and closes the page of properties leaving the values that appear.

It turns the sphere 90 degrees in x-axis.

It duplicates the sphere (ctrl.+ D) and reduces the new sphere uniformly (scale presses X stops to activate the transformation and manten pressing shift while you drag the mouse) until it is his size is 0,97.

Key T for the selection of points presses now, and in the Right window it selects the points of the left end as it is seen in the drawing.



Scale in local way that selection to -2,3, (introducing that numerical value in the square " and " of scale), moves that same selection of points 0.75 units of Softimage towards the interior of the sphere.

It selects the outer sphere now, and again it selects the points that the following image shows.



This selection to 2,5 climbs.

With this, already we have the form of the eye, the rest we will do it using textures.

The button in the right superior part of window b presses to extend the camera Vista.

You do to render of window on the spheres. They appear with the gray material of the scene, and we can solely see the outer sphere. We are going to create new materials for these objects.

It selects the outer sphere and in the module of Render (3) > selects to Material Get > Phong. Apparently nothing has changed in render (the sphere already had pong applied but it was the generic material of the scene that is applied to all the new objects. Whenever we are going to make changes on the material we will have to create a new material, otherwise the changes are applied to all the objects). The outer sphere is going to us to provide the brightness of the eye, we will have to increase the luminosity of the color to specular, for it we pressed button RGB, with which we will happen to the way of selection HLS, from we can here increase to the value of luminosity (l) changing the value by keyboard to 5. Also we are going to reduce the diffusion of the specular brightness (to specular decay) giving a value of 400, also by keyboard.

The superior eyelash Transparency/Reflection presses, we will be able here to increase the value of transparency of the material, we can use the color bars (pressing CTRL. So that the three move simultaneously) until a value of 0.85 approximately. Also we are going to slightly raise the value of the refractive index 1,06. And with this we can close goes window of properties of the material.

We will select the other sphere now. Tree is this case we are going to use the properties of combination of render to generate the texture of the eye. Key 7 presses to open the window of Render Tree. We can fit the size of this floating window and change the point of view of the camera to be able to see l simultaneously scene and render tree.

Pressing update in l Render Tree we made sure that the representation of that Vista belongs to the selected sphere. As the outer sphere already produces the brightness, we will assign a material without property to specular to this sphere. Material Get > > Lambert.

The material would have to also change in the Render Tree. Within the Render Tree we selected a new one to shader to generate the Nodes texture > Texture > Gradient, a new element appears in the space of the Render Tree, we must connect selected and dragging the red point of the node gradient to the properties ambient and diffuse of the node Lambert.

Double click on the Gradient node and in the pagina of properties that appear we assigned a new projection of texture in New>UV, the rainbow that forms this texture, badly is oriented, to reorient it we pressed in the publisher of properties of the Edit texture and activated Swap UV, first of the options that appear in the new window.



We pressed in the icon of the arrow backwards to finish publishing the texture.



We pressed the eyelash of Gradient colors in which we will modify the values so that they agree with those of the following table.



The steps that we have followed have been:

1. - To establish number of colors in 7.

2. - To increase spread position of color 2 up to 0,84; the one of color 4 to 0,88; the one of the 0.94 color 6 to and the one of color 7 to 1.

There are certain jumps of color between which it does not interest degrading to us, but an abrupt change of color, we will use equality expressions to establish these parameters.

3. - To press on the icon of animation (the green point) of spread position of color the 2 and arrástralo pressing ctrl. on the icon of equivalent animation of color 3. The same operation with the icon of color 6 repeats on the one of color 5.

4. - To establish values of 0.0.0 for RGB for color 6, black color. To press on the panel of color reference that we finished modifying, dragging it and loosen it on its equivalent panel for color 7.

5. - It changes to the maximum (1) value R of color 1 to have red an intense one.

The result of all these changes would have to be similar to this image.



To press with the right button of the mouse on the icon of connection to the right of values RGBA of color 4, this unfolds a menu with the textures that can be applied, we must select fractal.



The page on that we were working transforms into the page of properties of the texture fractal. Again it requests a texture projection to us, although in this case we did not need to create a new one, since we can reuse the one that we have applied previously, pressing on the triangle at the end of the box of dialogue and selected Texture_Projetion.

Within this same page of properties we changed to the Advanced eyelash now and there we modified the maximum values by 50, 30, 10 to obtain the radial form characteristic of a rainbow.

It presses the eyelash fractal and it blocks this table (activating the icon in lock form it arrives at the right).

Beam double click on the Gradient node, of the Render Tree that will unfold the previous table of colorores of the gradient.

Colors 1 and 2 of the fractal and the 3 and the 5 of the gradient control l pigmentación of the rainbow. Modifícalos to your pleasure. An example:



This it is a good moment to keep the scene.



PART 2: To create controls for animation

Once finished the modeled one and texturado we are going to turn the result into a model. We selected both spheres, we pressed key 1 to happen to the menu of modeled to Create > Model > New.

The model is the element of reference at the time of using controls, like a container.

In order to create a table of controls we pressed 2 to pass to the menu of animation and from Create > Parameter > New Custom Parameter Seth to create a table of parameters there.

We could include different parameters to control different parameters related to the animation (movements, etc.), in this case we will only create one of these parameters to see its operation. Create > Parameter > New Custom Parameter. In the table of properties we changed the name of the parameter (by Param defect) by " Expansion of the rainbow " and left the rest of values as they come by defect.

Now whenever we select the model of the eye we can find between its properties (in a Explorer window or the Selection button of the menu of the right) the table of parameters that we have created. With double click we can open it and there " expansion of the rainbow " will be the parameter, although at the moment he is not tie to anything. The icon of the lock in the right superior part blocks this table activating.

In render Tree we click double on the Gradient node and activated the eyelash Gradient Colors.

It changes to the value of spread position in color 6 of the gradient up to 0,98; spread presses with the right button of the mouse the icon of animation of that position and chooses the option of the Link menu with looks for in the Vista Explorer that unfolds the parameter " expansion of the rainbow " that we had created. This creates a relation between the values of both parameters.

" expansion of the rainbow " moves the sliding bar of the parameter (value of 1) to the maximum changes again to the value of spread position in color 6 of the gradient up to 0,93; spread again presses with the right button of the mouse the icon of animation of that position (that now has form of L with a curve raises) and this time relative chooses the option Seth values. As of this moment it has two values of reference tying both parameters and will make a interpolación for the rest of values, now if, if we move the bar of our customized parameter the expansion of the rainbow changes.

It presses on the icon with form of L and a curve and arrástralo until the value of spread position of color 4. Of this form we were able to tie different parameters from the same control. It presses with right button on the new tie icon of color 4, in the menu chooses Publishing the Animation option. The curve that appears in the publisher is not exactly a curve of valor/tiempo, this relates the value of this parameter of spread to the value of the control of expansion of the rainbow (valor/valor), we can modify the curve slightly moving it so that it fits the aspect in the different values from expansion.