diff --git a/src/ActivityAnimation.cpp b/src/ActivityAnimation.cpp
index 04039dd..51de794 100644
--- a/src/ActivityAnimation.cpp
+++ b/src/ActivityAnimation.cpp
@@ -4,32 +4,25 @@
 #include <GL/gl.h>
 #include "Range.hpp"
 #include "ActivityAnimation.hpp"
-#include "utils.hpp"
 
+using namespace std;
 using namespace fmri;
 
-static inline float correct_timescale(float original)
+ActivityAnimation::ActivityAnimation(const vector<pair<DType, pair<size_t, size_t>>> &interactions,
+                                     const float *aPositions, const float *bPositions, float xDist) :
+        bufferLength(3 * interactions.size())
 {
-    float ignore;
-    return std::modf(original, &ignore);
-}
+    startingPos.reserve(bufferLength);
+    delta.reserve(bufferLength);
 
-ActivityAnimation::ActivityAnimation(std::size_t count, const float *aPos, const float *bPos, const float xDist) :
-        bufferLength(3 * count),
-        startingPos(bufferLength),
-        delta(bufferLength),
-        offset(bufferLength)
-{
-    memcpy(startingPos.data(), aPos, sizeof(aPos[0]) * bufferLength);
-    for (auto i : Range(bufferLength)) {
-        delta[i] = bPos[i] - aPos[i];
-    }
+    for (auto &entry : interactions) {
+        auto *aPos = &aPositions[entry.second.first];
+        auto *bPos = &bPositions[entry.second.second];
 
-    auto& random = rng();
-    std::uniform_real_distribution<float> rd;
-    for (auto i : Range(count)) {
-        offset[i] = rd(random);
-        delta[3 * i] += xDist;
+        for (auto i : Range(3)) {
+            startingPos.emplace_back(aPos[i]);
+            delta.emplace_back(bPos[i] - aPos[i] + (i % 3 ? 0 : xDist));
+        }
     }
 }
 
diff --git a/src/ActivityAnimation.hpp b/src/ActivityAnimation.hpp
index 3513195..369e88d 100644
--- a/src/ActivityAnimation.hpp
+++ b/src/ActivityAnimation.hpp
@@ -4,6 +4,7 @@
 #include <memory>
 #include <vector>
 #include "Animation.hpp"
+#include "utils.hpp"
 
 namespace fmri
 {
@@ -11,13 +12,13 @@ namespace fmri
             : public Animation
     {
     public:
-        ActivityAnimation(std::size_t count, const float* aPos, const float* bPos, const float xDist);
+        ActivityAnimation(const std::vector<std::pair<DType, std::pair<std::size_t, std::size_t>>> &interactions,
+                                  const float *aPositions, const float *bPositions, float xDist);
         void draw(float timeScale) override;
 
     private:
         std::size_t bufferLength;
         std::vector<float> startingPos;
         std::vector<float> delta;
-        std::vector<float> offset;
     };
 }
\ No newline at end of file
diff --git a/src/visualisations.cpp b/src/visualisations.cpp
index 7435f57..2d68faf 100644
--- a/src/visualisations.cpp
+++ b/src/visualisations.cpp
@@ -72,16 +72,6 @@ Animation * fmri::getActivityAnimation(const fmri::LayerData &prevState, const f
     }
 
     const auto entries = computeActivityStrengths(prevState, layer);
-    const auto bufferSize = 3 * entries.size();
 
-    unique_ptr<float[]> startingPositions(new float[bufferSize]);
-    unique_ptr<float[]> endingPositions(new float[bufferSize]);
-
-    LOG(INFO) << "Creating position buffers for interaction in " << layer.name() << endl;
-    for (auto i : Range(entries.size())) {
-        memcpy(startingPositions.get() + 3 * i, prevPositions.data() + 3 * entries[i].second.first, 3 * sizeof(float));
-        memcpy(endingPositions.get() + 3 * i, curPositions.data() + 3 * entries[i].second.second, 3 * sizeof(float));
-    }
-
-    return new ActivityAnimation(entries.size(), startingPositions.get(), endingPositions.get(), 2.0);
+    return new ActivityAnimation(entries, prevPositions.data(), curPositions.data(), 2);
 }