3d Ray Tracing and Surface Manipulation Facility

Introduction

In addition to tracing rays, programs are provided for dealing with surfaces, curves, and volumes. Computing normals to surfaces, and creating surfaces from normals are provided by the *PtNorms* programs. Generalized interpolation, extrapolation, and smoothing on grids is provided by the grids2grid and scatterd2grid programs. And translation between various formats and representations are provided.

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Methods are provided for tracing rays from depth to time and from time to depth; for creating ray starting positions and directions, and for filtering ray positions and directions according to windows in the parameters and horizontal travel distance. In addition, various utilities for dealing with surfaces and curves are provided. Generalized extrapolation, interpolation, and smoothing on regular grids are provided by the grids2grid program. And irregularly sampled data may be cast onto a regular grid using the scattered2grid program.

The ray tracer has been designed to read through the velocity model ONLY once. Thus all of the rays are traced through each depth level at the same time. This allows various optimizations which may speed up the computation. However, rays that reverse direction would require revisiting previous depth levels and conflict with these optimizations. Therefore these rays are "killed" by the ray tracer. Methods are provided for filtering "dead" rays.

R&D Documentation

Description Programs Type of Document
Ray Tracing
Tracing 3d rays from depth to time d3depth2timeman page
Tracing 3d rays from time to depthd3time2depthman page
Creating Ray Starting Information
Create PtNorms by computing normals to dds surfacesgrid2ptnormsman page
Create PtNorms from gridsgrid2PtNormsman page
Compute normals to dds surfacesusp2PtNormsman page
Create PtNorms from old style gOcad trisurfs3dtrisurfnormalsman page
Using the Ray (PtNorms) Information
Convert PtNorms to gocad Vertex SetsPtNorms2vsman page
Convert PtNorms to gocad surfacesPtNorms2trisurfman page
Convert PtNorms to gocad time surfacesPtNorms2trisurfTman page
Convert gOcad triangulated surfaces to dds grids (interpolating to fill triangles)3dtrisurf2gridman page
Convert PtNorms to dds volumesPtNorms2volumeman page
Filter PtNorms paramterscPtNorms_Filterman page
Filter PtNorms by horizontal travelPtNorms_Filterman page
Filter for matched pairs of incident and reflected raysPtNorm_angle_Filterman page
Filter for matched pairs of incident and reflected raysPtNorms_Offset_Filterman page
Create matched pairs of incident and reflected raysPtNorms2PtNorms_angleman page
Smooth a grid of valuesgrid2gridman page
Create a grid from a PtNorms filePtNorms2gridman page
Create a PtNorms file from a grid filegrid2ptnormsman page
Interpolate, extrapolate, and/or smooth surfaces defined on regular grids.grids2gridman page
Interpolate, extrapolate, and/or smooth single valued surfaces defined by irregularly sampled points.scattered2gridman page
Translate landmark surfaces into regular grids or Gocad vertex sets.landmark2surfman page
Extract a perimeter from a landmark surface and translate it into a Gocad Pline.landmark2plman page
Create a GOCAD vertex set from a regular gridded surface.grid2vsetman page
Create a GOCAD vertex set from a landmark ascii file of line and depth indices.landmark_lidi2vsman page
Create a GOCAD vertex set from a landmark ascii file using the true location of the data.landmark_UTM2vsman page
Translate new GOCAD objects into old stle GOCAD objectsnew2oldman page
Translate voxet header to a dds dictionaryvo2ddsman page
Interface to the Landmark Environment
Translate landmark horizons into regular dds grids from Landmark Environment.landmarktoddsman page
Translate regular dds grids into landmark horizons.ddstolandmarkman page

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Exploration Production & Technology Group
Daniel Vasicek

Daniel J. Vasicek
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