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[Maarten Moesen <>]

Sebastien, Thank you for your clear answer!

Maarten
--
Maarten Moesen, PHD
Polymer Physicist Computational Modeling

HUNTSMAN (Europe) BVBA
Everslaan 45
B-3078 Everberg
Belgium
VAT: BE - 0468.807.829

Office Phone: 0032 (0) 2 758 9962


 wrote on 01/10/2018
09:39:48 AM:

> From: "Sebastien Loriot (GeometryFactory)" <>
> To: , 
> Date: 01/10/2018 09:40 AM
> Subject: Re: [cgal-discuss] AABB tree: (t, u,
v) coordinates 
> directly from ray triangle intersection?
> Sent by: 
> 
> On 01/09/2018 10:29 AM, Maarten Moesen wrote:
> > Dear CGAL community,
> > 
> > First of all my best wishes for 2018 to the CGAL team and community!
> > 
> > Question 1:
> > In the AABB tree package there is plenty of support for (closest)
> > ray-triangle intersections which (very precisely) return a point
or a 
> > line segment. It could be, however, somewhat more convenient
for my code 
> > to work directly with the ray's intersection distance parameter
(t). In 
> > the documentation I've found a AABBRayIntersectionTraits Concept
that 
> > describes this. Is it meant to be used directly and if so, is
there also 
> > a model/example that shows how to?
> > 
> 
> This is something that must be provided to the algorithm so that it
can
> compute the closest intersected primitive.
> There is no API to get the t value of the first primitive intersected.
> The variable t is local to the function ray_intersection in there:
> https://urldefense.proofpoint.com/v2/url?
> u=https-3A__github.com_CGAL_cgal_blob_master_AABB-5Ftree_include_CGAL_internal_AABB-5Ftree_AABB-5Fray-5Fintersection.h&d=DwIC-
> g&c=XEmjTyjfAPcP2RtAp-6FGA&r=m_cDzmT5gx2T28-wSEGolLNtn-S-
> ReoPoEIWT7yrZso&m=DT4SMnoWaWxO4DO3fkKu8rQzcRWMdpp43FwD-nI-
> gZM&s=N79x8VEclx4oEXcmWyaaIKFb30R6i8pyAcMnwFrqtX0&e=
> 
> > Question 2:
> > I'm also interested in the texture coordinates (often denoted
with 
> > (t,u,v)) of the intersection of a ray with a triangle. Would
this be 
> > possible to obtain them directly or is it better to back-project
the 
> > point of intersection on the triangle?
> > 
> I don't think we have something better than computing the intersection
> point inside the triangle and then get its barycentric coordinates.
> 
> Sebastien.
> 
> 
> > Best regards,
> > 
> > Maarten
> > --
> > Maarten Moesen, PHD
> > Polymer Physicist Computational Modeling
> > 
> > HUNTSMAN (Europe) BVBA
> > Everslaan 45
> > B-3078 Everberg
> > Belgium
> > VAT: BE - 0468.807.829
> > 
> > Office Phone: 0032 (0) 2 758 9962
> 
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