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<HTML>
<HEAD>
<TITLE>VRweb Edit Dialogs</TITLE>
</HEAD>
<BODY background="vrwebbg.gif">
<H1>VRweb Edit Dialogs</H1>
<p>
<IMG ALT="VRweb" WIDTH="129" HEIGHT="40" SRC="vrwebsmall.gif">
<p>
After discussion of special <A href="#types">field types</A> you get help on
<p>
<UL>
<LI><A href="#insert">creating/inserting new objects</A>
<LI><A href="#anchor">set up anchors</A>
<LI><A href="#texture">apply/edit textures</A>
<LI><A href="#material">apply/edit materials (colors)</A>
<LI><A href="#structure">view/modify the scene structure</A>
<LI><A href="#transform">edit transformation values</A>
<LI><A href="#viewpoints">edit viewpoints</A>
<LI><A href="#grid">use the grid tool</A>
</UL>
<p>
See also <A href="edit.html">part 1</A> of the VRweb VRML Editor help.
<p>
<A name="types"></A>
<H2>Field Types</H2>
<p>
<UL>
<LI><b>URL</b>s may be given absolute (http://...) or as filenames,
optionally with a path relative to the current directory. (You should
start VRweb in the directory of the edited scene to get relative
references right.)
<p>
<LI><b>rotations</b> are given as a rotation axis an angle in radians.
A value of pi (3.14159...) represents a rotation about 180 degrees.
</UL>
<p>
<HR>
<p>
<A name="insert"></A>
<H2>Insert Object</H2>
<p>
With this dialog you can insert an object into your scene. First, <A
href="edit.html#selection">select</A> the group into which you want to
insert an object in the scene, or deselect anything to insert new
objects at the root level. Insertion will not work if you have
selected a geometric object.
<p>
In the upper listbox select the <i>object primitives</i> item, then
select one of Cone, Cube, Cylinder, or Sphere in the lower listbox.
Other items appear when you have installed object libraries (not yet
part of the distribution). Or select the <b>File</b> button, to insert
the contents of a file into your scene (physical copy as opposed to
URL reference). Select <b>Insert</b> to copy the data into the scene.
<p>
The bottom field editor lets you enter an <b>URL</b> or a relative
filename (see above) for a <i>WWWInline</i> node. Select
<b>Reference</b> to create the reference. <b>Known bug:</b> changes made
inside WWWInline nodes can not be saved.
<p>
<A name="anchor"></A>
<H2>Anchor Editor</H2>
<p>
Select an object or group and you may edit the anchor URL and/or
description to make a <i>WWWAnchor</i>. As for WWWInline nodes (see
above) the URL may be given absolute or relative. The description of
anchors is shown in the status line of browsers before following them.
Select <b>Apply</b> when done, <b>Reset</b> to restore the previous
values, or <b>Delete</b> to remove the link going out from the object.
<p>
While in edit mode, VRweb selects objects and not anchors with a
single left mouse click, thus you don't see the anchor description in
the status line.
<p>
It is not yet possible to use the items of the Anchors menu for this
purpose.
<p>
<A name="texture"></A>
<H2>Texture Editor</H2>
<p>
Using this dialog you can apply a <A
href="display.html#texturing">texture image</A> (<i>Texture2</i> node)
to the selected object or group. Either enter the <b>URL</b> (absolute
or relative, see above) or browse for a <b>File</b> to be used as
texture (the preview is only shown for local files). The listbox would
display textures of a library (not yet part of the distribution).
<p>
In the lower part of the dialog you may transform the texture by
translation, rotation, and scaling. Transformations affect texture
coordinates and not the image itself, so you e.g. have to scale by 0.5
to get the image twice as big. (The 2D rotation is specified by an
angle only.)
<p>
Select <b>Apply</b> when done or <b>Reset</b> to restore the previous
values. <b>Reload</b> will reload an image file that may have changed.
Clear the URL field and select Apply to remove an applied texture.
<p>
Creating texture coordinates for non-primitives (IndexedFacesets) is
not trivial, and not included in VRweb. Textures will only show up on
primitives and objects that have texture coordinates assigned. Also,
make sure you have activated <A
href="display.html#style">texturing</A> in the viewer.
<p>
<A name="material"></A>
<H2>Material Editor</H2>
<p>
With the material editor you can edit the appearance of an object (see
also <A href="display.html#lighting">lighting options</A>). The
material is made up of the following colors:
<p>
<UL>
<LI><i>Diffuse</i> Color: object base color, lit by light sources
(e.g. the headlight). This is the main part of the material and often
the only one you need to edit. It is also the color that will directly
be used when lighting calculations are turned off.
<p>
<LI><i>Ambient</i> Color: added to the diffuse color when lighting is
activated; gets multiplied with the intensity of the <A
href="display.html#color">ambient</A> light (usually low, e.g. 0.2).
Use a darker shade of diffuse or leave the default value.
<p>
<LI><i>Specular</i> Color is used to give objects a shiny (polished,
metallic) appearance; visible when light sources are nearly reflected
by the surface. Usually set to a grey shade to get a white highlight.
<p>
<LI><i>Emissive</i> Color: its absolute value added to the color; not
influenced by light sources. Useful to make objects look glowing
(without lighting other objects).
<p>
<LI><i>Shininess</i> Value: determines the size of the specular
highlight (the effect is best seen on curved surfaces). A small value
results in a diffuse highlight. Select one of the grey scales and
adjust the <b>L</b> slider (sorry for the bad interface).
<p>
<LI><i>Transparency</i> Value: ranges from 0.0 for complete opaque
objects to 1.0 for complete transparent (invisible) objects. E.g. 50 %
is half transparent. Select a grey scale and adjust the percentage
with the <b>L</b> slider.
</UL>
The buttons of the material editor have the same meaning as in the <A
href="display.html#color">color chooser</A>. Note that lighting
calcultaions are not handled equally accurate by all browsers. Many
scenes and materials (e.g. high specular component) look much better
with user defined light sources (cannot be edited with VRweb) than
with a headlight only.
<p>
<A name="structure"></A>
<H2>Structure Viewer</H2>
<p>
With the Structure Viewer you can examine the grouping hierarchy of
the scene. Groups are useful to apply transformations or properties to
a group of objects at once. The structure view is simplified by
showing only geometric objects and grouping nodes and not any
attribute nodes (e.g. Coordinates, Materials, Viewpoints etc.) which
you also find as nodes in the VRML file.
<p>
The buttons on the right side give quick access to the <b>View</b>
Selection feature and the <b>Selection</b> functions as described
under <A href="edit.html#selection">Object Selection</A>.
<p>
The lower button group provides access to the <A
href="edit.html#copypaste">copy and paste</A> operations. As mentioned
there, copy and paste operations create multiple object instances
(<i>DEF/USE</i>). You can edit these names in the <b>Name</b> field
at the bottom (hit return after entering a new name). You also see
multiple instances of the selected object with a special highlight in
the structure viewer.
<p>
<A name="transform"></A>
<H2>Transform Editor</H2>
<p>
This dialog complements the <A href="edit.html#objmanip">object
manipulation</A> interface. Edit the translation, rotation and scaling
values - in object or world coordinates.
<p>
Select <b>Apply</b> when done or <b>Reset</b> to restore the previous
values.
<p>
<A name="viewpoints"></A>
<H2>Viewpoint Settings</H2>
<p>
As you know, VRML allows the definition of multiple <A
href="navigate/index.html#viewpoints">viewpoints</A>. When viewpoints
were already defined you can select them in the lower listbox to jump
to them. Viewpoint names can be entered in the <b>Name</b> field
(press return after changing it).
<p>
To define new viewpoints, select the <b>Add</b> button. If you wish to
modify an existing viewpoint, select it in the list. Then <A
href="navigate/index.html">navigate</A> to the desired view. If you
wish to take the view over to the viewpoint, select <b>Set</b>;
otherwise just select the viewpoint again to return to the previous
values.
<p>
The camera parameters may also be edited in the fields in the upper
part of the dialog; the <b>Zoom</b> value (camera height angle in
radians) can only be set this way.
<p>
Finally, the <b>Delete</b> button deletes the selected viewpoint from
the list.
<p>
<A name="grid"></A>
<H2>Grid Settings</H2>
<p>
The grid shows how your scene is oriented in virtual 3D space. You
should remember that x points to the right, <b>y is up</b>, and z out
of the screen, forming a right-handed coordinate system. Grids are
displayed orthogonally to the selected <i>axis</i> (e.g. select y to
get a grid in the horizontal xz-plane). Using the sliders, you can
place them at arbitrary positions along their axis.
<p>
The <i>extent</i> of the whole grid and the <i>distance</i> between
the singe grid lines can be set with the other two sliders. All values
may be given in <i>absolute</i> values (as they are in the VRML file)
or <i>relative</i> to the current size of the scene. Select
<b>Apply</b> to apply the values to the grid or <b>Reset</b> to
restore the default values.
<p>
<HR>
<p>
<address>The VRweb editor functions have been programmed by Alexander
Nußbaumer. This documentation was written by Michael
Pichler.</address>
<p>
Back to <A HREF="vrwebhlp.html">overview</A>.
</BODY>
|
