how to get radius of sphere primitive

[Arthur~Chiu]

i want to get sphere primitive radius and center 

i use 

 

//primitive type par

GEO_Primitive       *prim;

GA_FOR_ALL_PRIMITIVES(gdp, prim)

{

   UT_BoundingBox   *sphere_bbox;

 

   GEO_PrimSphere *ss=(GEO_PrimSphere*)prim->castTo();

 

    ss->getBBox(sphere_bbox);

 

}

 

To compile successfully,but when i run it in houdini ,is error and exit houdini

i do not konw where is mistake?

 

[Storm Keeper]

There are two possible reasons why your code might crash. First is that your code doesn't allocate memory for sphere_bbox variable, and the second is that no checking is done to determine if the prim is actually an instance of GEO_PrimSphere class. And, by the way, calling the castTo() function does not work here. Can't tell exactly why, but it gives strange values. Maybe the call to this function destroys the information about the sphere itself, leaving only the basic data that belongs to GU_Primitive class? Would be interesting if someone more experienced explained this behavour.

 

So, the following code should work fine:

GEO_Primitive *prim;

GA_FOR_ALL_PRIMITIVES(gdp, prim)
{
    if (prim->getTypeId().get() != GA_PRIMSPHERE)
       continue;

    UT_BoundingBox *bb = new UT_BoundingBox();

    GEO_PrimSphere *ss=(GEO_PrimSphere*)prim;

    ss->getBBox(bb);
}

Edited June 22, 2014 by Dmitry Shurov

[Arthur~Chiu]

thanks