https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Clarification-on-RTC-GEOMETRY-TYPE-FLAT-LINEAR-CURVE-quot-u-quot/m-p/1172006#M825 <P>The documentation says "The intersection with the curve segment stores the parametric hit location<BR />along the curve segment as u-coordinate (range 0 to +1)."</P><P>As linear curves are represented as cylindrical segments, then a ray will intersect the cylinder in two places. Is the point represented by "u"&nbsp; the closest point of the "ray" to the line? Or is the projection of the 'first' intersection of the ray with the cylinder onto the line?</P> Mon, 18 Mar 2019 22:59:55 GMT AndrewC 2019-03-18T22:59:55Z https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Clarification-on-RTC-GEOMETRY-TYPE-FLAT-LINEAR-CURVE-quot-u-quot/m-p/1172006#M825 <P>The documentation says "The intersection with the curve segment stores the parametric hit location<BR />along the curve segment as u-coordinate (range 0 to +1)."</P><P>As linear curves are represented as cylindrical segments, then a ray will intersect the cylinder in two places. Is the point represented by "u"&nbsp; the closest point of the "ray" to the line? Or is the projection of the 'first' intersection of the ray with the cylinder onto the line?</P> Mon, 18 Mar 2019 22:59:55 GMT https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Clarification-on-RTC-GEOMETRY-TYPE-FLAT-LINEAR-CURVE-quot-u-quot/m-p/1172006#M825 AndrewC 2019-03-18T22:59:55Z https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Clarification-on-RTC-GEOMETRY-TYPE-FLAT-LINEAR-CURVE-quot-u-quot/m-p/1172007#M826 <P>It is the u-value of the closest point on the line to the ray.</P> Tue, 19 Mar 2019 05:48:20 GMT https://community.intel.com/t5/Intel-Embree-Ray-Tracing-Kernels/Clarification-on-RTC-GEOMETRY-TYPE-FLAT-LINEAR-CURVE-quot-u-quot/m-p/1172007#M826 SvenW_Intel 2019-03-19T05:48:20Z