Background Image

IRender can place a Background Image behind your model.

Use the Background Tab , and select an image to use as the background.


Background Tab

Image:Background 72.png

Background Image

Visibility

Projection

This determines how the image is projected onto the sky of background.

Offsets - for Planar Projections

Scales - for Planar Projections

Rotation - for Cylindrical and Spherical Projections.

Reset - resets Offsets, Scales and Rotation.

See: Background Image for examples.

Ground Plane

Ground Plane Materials

From the [[{{{1}}} Materials Dialog|Materials Dialog]] you can define and edit materials for the Ground Plane.

This lets you apply a grass texture for land, or a Procedural Bump Map and reflection to emulate water.

Alpha Transparent Ground Plane

With an Alpha Transparent Ground Plane, you can save the rendering as an Alpha Transparent image, and the ground plane will be transparent. However, shadows on the ground will be visible. This can be used to place the ground plane image on top of a background image and still see where the shadows would appear. (Of course this works best if you are placing he image on a flat surface.)




Visible and Reflected

This shows samples of the 4 possibilities for Background visible, and Background reflected.

A non-sky image has been used for the background, because it make it easier to wee when it is visible and when it is reflected.

Visible and Reflected background - visible on, reflected on This is normal, but there may be times when you want to see the background, but not reflect it in windows.
Visible and Reflected background - visible on, reflected on
This is normal, but there may be times when you want to see the background, but not reflect it in windows.
Visible but not Reflected background. - visible on, reflected off The background is visible - but not reflected in the dome.
Visible but not Reflected background. - visible on, reflected off
The background is visible - but not reflected in the dome.
Not Visible, butReflected background - visible off, reflected on This could ne used to reflect dramatic clouds without showing clouds in the sky.
Not Visible, butReflected background - visible off, reflected on
This could ne used to reflect dramatic clouds without showing clouds in the sky.
No background image used - visible off, reflected off
No background image used - visible off, reflected off


Background Projections

These determine how the image is projected onto the sky of background.

Here are some examples using the same sky background and 3 different projections.

Notice that the cylindrical and spherical projections stretch out the image more to fill the entire background. This may work properly with normal sky images, or you may need a 360 degree image to stretch around the cylinder or sphere.


Planar

Image fills render area. See Scales and Offsets below.
Image fills render area. See Scales and Offsets below.


Cylindrical

Image wraps around 360 degree cylinder.
Image wraps around 360 degree cylinder.


Spherical

Image wraps around 360 degree sphere.
Image wraps around 360 degree sphere.


Scales and Offsets

Here are some examples of scale and offset for Planar Backbrounds.

0% offset, 100% scale.
0% offset, 100% scale.
50% X offset - 100% scale.Notice it moves the image 50% to the left and repeats.
50% X offset - 100% scale.
Notice it moves the image 50% to the left and repeats.
0% X offset - 150% scale (X and Y).
0% X offset - 150% scale (X and Y).
50% X offset - 150% scale (X and Y).The X Offset seems to be effected by the scale.
50% X offset - 150% scale (X and Y).
The X Offset seems to be effected by the scale.


Horizon

If you check Adjust Center Line to Horizon, then the image will be scaled and offset so that the vertical centerline of the image matches the horizon of the current perspective view. If you have created your background image with the horizon in the center, then this provides a more realistic view - especially when seen through windows.


Background Image with horizon at center of image. (You can place the horizon at the center by enlarging the image in a Paint Program, shifting the image so that the horizon is in the center, and adding additional color above or below the image to complete it.
Background Image with horizon at center of image. (You can place the horizon at the center by enlarging the image in a Paint Program, shifting the image so that the horizon is in the center, and adding additional color above or below the image to complete it.
rendered scene without background image to show the location of the horizon. Not that the horizon is not in the center of the rendered area.
rendered scene without background image to show the location of the horizon. Not that the horizon is not in the center of the rendered area.
Rendered image with background adjusted to match the horizon.
Rendered image with background adjusted to match the horizon.


See also