arzezniczak Posted December 20, 2018 Share Posted December 20, 2018 Hello, I've got some mesh imported from OBJ with pretty complex geometry (many triangles). I'm adding grass as a child object of that mesh and setting proper x and y size that whole mesh is inside grass. I've expected to see grass spawned evenly all around my mesh, but instead I've always have triangles without any grass. No matter what I change in grass settings (seed, size, step, subdivision, density, angle, orientation, node location) always the same triangles have grass and other have not. I've attached sample project. grass_on_hill_bug.zip Link to comment
morbid Posted December 21, 2018 Share Posted December 21, 2018 Hi arzezniczak, intersection malfunctions in your case because of two issues: Tangents of your mesh are incorrect - each vertex has at least 4 vectors This mesh is two-sided, which also may cause this. I assume this model was created for terrain, if so, it's better to use casual one-sided geometry. For instance, this is a mesh I created from sphere in Unigine Editor. As you can see each vertex has only one set vectors. This is your mesh: To check this I created a mesh from your model (RMB -> Create mesh) and opened it in Resource editor. You can find this tool in <sdk>/bin folder. So, I suggest the following: fix tangents in the 3d editor you'd used switch to one-sided mesh Thanks. 1 How to submit a good bug report --- FTP server for test scenes and user uploads: ftp://files.unigine.com user: upload password: 6xYkd6vLYWjpW6SN Link to comment
arzezniczak Posted December 21, 2018 Author Share Posted December 21, 2018 Thank you very much for detailed answer! I agree - tangents from our 3d modeller was mess and two-sided mesh was overkill in this object. After fixing this problems grass works perfectly on hills. Thank you! Link to comment
morbid Posted December 21, 2018 Share Posted December 21, 2018 We're glad to help! How to submit a good bug report --- FTP server for test scenes and user uploads: ftp://files.unigine.com user: upload password: 6xYkd6vLYWjpW6SN Link to comment
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