Displace

Publish date: 2024-05-08

This tool imprints a preferably black-and-white image onto a surface or an object, by meshing the surface and then pulling or pushing the tiles of the mesh according to the color of the image, thus producing 3D surfaces. To apply the operation, with the tool active, click on the surface or on the object. This tool initially has no tool options, but as soon as an object is picked the Displacement Edit dialog is invoked. It contains a variety of settings that will control the details of the displacement operation and also a Preview area where the current status of the operation and the effects of the different options may be displayed.

D_Displacement Edit

Displacement Edit dialog.
D_Displacement Map D_Displace_View
Displacement Map Options dialog.
 
Displacement Map View dialog.

Under the Preview area ar the usual controls for navigating the view and selecting a display mode. Further down there is a view of the currently linked displacement map. Its proportions can be adjusted or a new map can be selected. Clicking in the map preview area invokes the Displacement Map Options dialog (see previous page), which contains a few buttons in addition to the displacement image.

Pressing View... invokes the Displacement View dialog, shown on the previous page. It again displays the displacement map in its window in a red boundary frame. Points marked on this frame can be dragged to resize the image. Pressing Load... allows you to load another image. Any bit map based image file can be used as a displacement map.

When Use Alpha Channel is on, the gray scale value in the image's 4th (or alpha) channel is used, rather than that in the red-green-blue channels. When Invert is on, the gray scale information is inverted (black becomes white and vice versa).

Either the Original or the Displaced object can be previewed by selecting the respective button. When the former is on, you have the option to Draw Tiles and/or turn on Snap. The original object is used to select the one or more faces where displacement will occur and there are two buttons to Select All Faces or to Deselect All Faces.

When Displaced is on, the shape of the object after displacement has been applied is previewed. The displacement itself is affected by a variety of parameters set on the right side of the dialog. To see the effect of each new setting, after you change a parameter, press Update. You need to do this or otherwise your changes will not be visible.

Origin, Rotation: The values in these fields determine the position and orientation of the displacement coordinate system. Pressing Center places the origin at the center of the object and pressing Reset sets all rotation angles to 0's.

Mapping Type: There are three: Flat, Cylindrical, and Spherical. These are similar to those used for mapping textures onto surfaces.

Horizontal / Vertical Tiling: The options in these groups control the placement of the displacement image (map) relative to the object that will be displaced. Size is the size of the image. When Center is on, the image is centered relative to its origin. Otherwise, its lower-left corner is placed on the displacement origin. When Mirror is on, the image is mirrored in the respective direction. When Infinite is on, as many images as necessary to cover the length of the object are placed in the respective direction. Alternatively, numbers may be entered in the Times fields, indicating exactly how many times the image will be repeated. The default is 1.

Lock Size To: This pop-up menu allows you to set the proportions of the displacement map to a specific value. That is, if the size in one direction is changed, the other is adjusted automatically to maintain proportions according to the selection from this menu. There are five options: None imposes no restrictions and causes no adjustment. Square Tile causes the horizontal and vertical tile sizes to be equal. Current Proportions causes the proportions to be set to the proportions present at the time this menu was last selected. Displacement Map preserves the proportions of the displacement image. Object Extents causes the tile sizes to be automatically adjusted to a round number of copies that fit exactly across the object, in its respective direction.

Min, Max: These values represent the displacement applied to each point of the image, which is relative to its gray scale. White indicates the maximum displacement, while black is the minimum. If 0 is entered in Min, all black areas will remain at the level of the original surface. If a negative number is entered, cavities will be created for the black areas.

Smoothness: The value set through this slider bar or entered in its field controls the smoothness relative to the original displacement image. A 0 preserves the smoothness of the image. Larger values apply a blur, which softens sharp areas, resulting in smoother curves and some loss of detail.

displace_face_flat.pict  Displace.jpg
Displacement Map
 
Displaced Object
displace_topo_new.PICT displace_topo_new
Displacement Map
 
Displaced Object

Adaptive Meshing: This group of options offers additional means for meshing objects, when the initial meshing appears rough and insufficient. This type of meshing recursively subdivides the original faces as needed to match the details of a displacement. The three available options determine how many times a face will be subdivided.

Max # Of Subdivisions: indicates the maximum number of times a face may be subdivided. Choose the number with caution because even small numbers may generate a large number of faces. Max Segment Length imposes a size limit to the subdivision process. Threshold is a percentage that controls the level of subdivisions in areas where there are significant differences in grayscale tones. To decide whether a tile will be farther subdivided, color samples are take at the center and the corners of the tile. If the difference in gray tone is less than this value, no more subdivisions are performed. Thus, lower Threshold values cause more subdivisions. When this value is 0 (the default) it essentially imposes no limits. The level of subdivision is ultimately determined by a combined evaluation of these three parameters.

Triangulate Mesh: triangulates the tiles the process generates.

Smooth Mesh: only applies to spherical and cylindrical mapping. If on, the meshed object first takes a cylindrical or spherical shape and then the displacement is applied, which results in a smoother mesh. See example below.

displace_non_smooth.pict displace_smooth.pict
Spherical displacement with Smooth Mesh on.
 
Spherical displacement with Smooth Mesh off.

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