C_STMap

The C_STMap node is a GPU accelerated version of CaraVR's standard STMap node. The C_STMap node allows you to warp the src input according to the stitch or ppass attached to the map input. C_STMap accepts stitch_map and ppass_map channels in specified layers. The stitch_map UV channels represent the absolute pixel positions of an image normalized between 0 and 1, whereas the ppass_map XYZ channels represent the normalized 3D coordinates of a latlong image ranging between -1 and 1.

Inputs and Controls

Connection Type

Connection Name

Function

Input

map

The input you want to use to warp the source image.

src

The source image to which you want to apply the effect.

Control (UI)

Knob (Scripting)

Default Value

Function

C_STMap Tab

Local GPU

gpuName

N/A

Displays the GPU used for rendering when Use GPU if available is enabled. Local GPU displays Not available when:

Use CPU is selected as the default blink device in the Preferences.

no suitable GPU was found on your system.

it was not possible to create a context for processing on the selected GPU, such as when there is not enough free memory available on the GPU.

You can select a different GPU, if available, by navigating to the Preferences and selecting an alternative from the default blink device dropdown.

Note:   Selecting a different GPU requires you to restart CaraVR before the change takes effect.

Use GPU if available

useGPUIfAvailable

enabled

When enabled, rendering occurs on the Local GPU specified, if available, rather than the CPU. The output between the GPU and CPU is identical on NVIDIA GPUs, but using the GPU can significantly improve processing performance.

CaraVR supports AMD GPUs on late 2013 Mac Pro 6,1, mid 2015 Mac Pro 11,5, and and late 2016 MacBook Pro 13,3, running OS X 10.9.3 'Mavericks', or later. While, in some cases the bit-wise equality between GPU and CPU holds, for some operations there are limitations to the accuracy possible with this configuration.

Note:  Enabling this option with no local GPU allows the script to run on the GPU whenever the script is opened on a machine that does have a GPU available.
You should also select this if you wish to render from the command line with the --gpu option.

GPU processing also requires certain NVIDIA and AMD drivers. For more information on the minimum requirements, please refer to the Nuke Release Notes available in Help > Release Notes.

Channels

channels

all

The effect is only applied to these channels.

If you set this to something other than all or none, you can use the checkboxes on the right to select individual channels.

Map

map

stmap

Sets the map representation to use:

stmap - a two channel UV map.

ppass - a three channel XYZ map.

uv

none

Sets the channels used to calculate the mapping for the src input. The selected layer must contain at least two channels for stmap maps or three channels for ppass maps.

Filter

filter

Cubic

Selects the filtering algorithm to use when remapping pixels from their original positions to new positions. This allows you to avoid problems with image quality, particularly in high contrast areas of the frame (where highly aliased, or jaggy, edges may appear if pixels are not filtered and retain their original values).

Nearest - applies no filtering.

Bilinear - relatively fast to process, but can produce poor results at higher zoom levels. You can use Bilinear to preview a transform before using one of the other resampling types to produce your output.

Bicubic - the default filter. A smoother filter that produces less artifacts than Nearest and Bilinear, but takes longer to process.

Mitchell - remapped pixels receive some smoothing, plus blurring to hide pixelation.

Lanczos - remapped pixels receive sharpening, which can be useful for scaling down. This filter takes the longest to process.

Smoothness

smoothness

1

When Filter is set to Mitchell, this affects the amount of smoothness, or blur, applied to the filter.

Sharpening

sharpening

0

When Filter is set to Mitchell, this affects the amount of sharpening applied to the filter.

Radius

radius

3

When Filter is set to Lanczos, this affects the amount of sharpening applied to the filter.

Output

mode

Warped Src

Sets the output mode:

Warped src - warps the src input using the map input.

Warped src (inverse) - warps the src input using the inverse of the map input.

Map inverse - writes the inverse of the input map to the channels selected in the Map control. This option doesn't require an src input.

Splatting

splatting

2

Controls the maximum splatting radius used to fill in missing areas of the inverse map.

You can increase the radius to fill in large areas, but high values can produce artifacts in the final output.

Note:  This control is only available when Output is set to Warped src (inverse) or Map inverse.

Interpolate

interpolate

disabled

When enabled, missing data from inverse maps is filled in using a simple interpolation method.

When disabled, any missing data is filled in black.

Note:  This control is only available when Output is set to Warped src (inverse) or Map inverse.

mask

N/A

disabled

Enables the associated mask channel to the right. Disabling this checkbox is the same as setting the channel to none.

maskChannelInput

none

The channel to use as a mask. By default, the roto shapes are limited to the non-black areas of this channel.

inject

inject

disabled

Copies the mask input to the predefined mask.a channel. Injecting the mask allows you to use the same mask further downstream.

invert

invert_mask

disabled

Inverts the use of the mask channel, so that output is limited to the non-white areas of the mask.

fringe

fringe

disabled

Blurs the edges of the mask.