Day 47 & 48


Here's a walkthrough of a method which enables user to:
1) Import a low-poly geometry.
2) Tweak the geometry in 3 different sections of the geometry regardless of shape and size.
3) Apply a layer of vopsop as shown in previous walkthrough. (See day 40)
4) Render bgeo.

Special thanks to Mr Ron for cracking his brains over this method. I could have never come up with all the expressions myself without his help.


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Import in a low-poly base mesh and subdivide it. Don't subdivide it too much or you'll face PC crashing based consequences later.

Create 3 transform nodes to act as the following functions:

1) Rotate geometry about it's pivot to fit bounding boxes which are meant to capture top, middle and bottom points of geometry. Rotation will be defined by user.

2) Center to centralize geometry and zero out transformations.

3) Normalize geometry to fit into the scale of 1 unit for bounding boxes to act upon.

Create 3 bounding box groups to control the top, middle and bottom of the geometry. The bounding boxes will grab certain points of the geometry (based on where it's position) so that transform nodes can be applied to edit those parts.

Expressions used:

bbox("../xform_center", D_YSIZE)/3

In the Y channel of Size attribute. This expression controls the size of a bounding box. It divides the scale in Y axis by 3 according to the geometry. Thus this allows all 3 bounding boxes to fit into the 1 unit the geometry is confined to.

centroid("../xform_center", D_Y) - or + bbox("../xform_center", D_YSIZE)/3

In the Y channel of center attribute. This expression is used to position a bounding box right in the middle of the geometry. Subtract or add the previous expression to position the bounding box bottom or top.

centroid("../xform_center", D_Y) + bbox("../xform_center", D_YSIZE)/3

centroid("../xform_center", D_Y)

centroid("../xform_center", D_Y) - bbox("../xform_center", D_YSIZE)/3

Create 3 softTransform nodes, each softTransform node will control the points of the geometry within a bounding box by reading a group name.

The softTransform nodes will be for the user to twist the geometry and make the rock more organic looking.

Create 3 more transform nodes. These will be used to reverse the rotate, center and normalize nodes. The edited geometry will then be transformed back into its original scale and position.

Reverse Normalization

Reverse Centralization

Reverse Rotation

Add a pre-generated vopsop layer onto the geometry for additional rock details.

Here would be a good time to increase subdivisions slowly to see extra details pop up.

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This section of screen shots shows how a user will use this rock generator before I turn it into a digital asset.