burakdogancay 1 Posted September 7 Hi, I am using Unigine 2.8. I want to get terrain normal with respect to ENU coordinate system but I have some problems. Let's start with first problem. I have a GeodeticPivot where its pivot is located on the Earth at (39.1201340430776554, 35.1688556961649041, 0). I think this is the origin of my play area in geo coordiantes, anyway. Now by using getENUWorldRotation method of the Ellipsoid class I did the following: Unigine::GeodeticPivot pivot = Unigine::GeodeticPivot::cast( Unigine::Editor::get()->getNodeByName("GeodeticPivot") ); Unigine::Math::quat originQuat = pivot ->getEllipsoid()->getENUWorldRotation(Unigine::Math::Vec3(0,0,0)); Here, Unigine::Math::Vec3(0,0,0) is the origin of GeodeticPivot in ellipsoid coordinates, right? What is the definition of the ellipsoid coordinates? Are the ellipsoid coordinates not the coordinates I see in the editor? Now what I expect is that originQuat is the identity quaternion. But it is not. originQuat is (0.5, 0.5, 0.5, 0.5). This is confusing. What am I doing wrong? Next I tried following for getting terrain normal at the world position of a node with respect to ENU coordinate system whose origin is the world position of this node. For example if the terrain is completely flat at this position, I expect that the normal is (0,0,1) wrt to ENU coordinate system whose origin is the world position of the node. Anyway, here is the my solution. Unigine::Math::Vec3 flat, dummy; pivot->mapEllipsoidToFlat(node->getWorldPosition(), flat, dummy); Unigine::Math::vec3 normalF; Unigine::Math::vec3 upF; terrain->fetchTopologyData(flat.x, flat.y, flat, normalF, upF, 1); Now I must tansform normalF to ENU coordinates whose origin is at node->getWorldPosition(). Unigine::Math::quat quat = pivot->getEllipsoid()->getENUWorldRotation(node->getWorldPosition()); normalF = Unigine::Math::inverse(quat) * normalF; This code should transform normalF to ENU coordinates. But it doesn't work. I am getting weird results. Thank you for your help in advance. Share this post Link to post