Cycles: fix objects disappearing when starting or stopping movement.

Another issue with the modified particle motion blur fix: since
pre and post are used as validity markers, they must be set even
if there is no actual motion, like the original bool flags were.
Otherwise an object starting to move or stopping is interpreted
as having invalid blur data and hidden.

1 files changed, 8 insertions, 6 deletions

diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index c34dec3be51..f305e8e17cc 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -329,16 +329,18 @@ Object *BlenderSync::sync_object(BL::Object& b_parent,
 			/* object transformation */
 			if(tfm != object->tfm) {
 				VLOG(1) << "Object " << b_ob.name() << " motion detected.";
-				if(motion_time == -1.0f) {
-					object->motion.pre = tfm;
-					object->use_motion = true;
-				}
-				else if(motion_time == 1.0f) {
-					object->motion.post = tfm;
+				if(motion_time == -1.0f || motion_time == 1.0f) {
 					object->use_motion = true;
 				}
 			}
 
+			if(motion_time == -1.0f) {
+				object->motion.pre = tfm;
+			}
+			else if(motion_time == 1.0f) {
+				object->motion.post = tfm;
+			}
+
 			/* mesh deformation */
 			if(object->mesh)
 				sync_mesh_motion(b_ob, object, motion_time);