diff --git a/libs/image/kis_distance_information.cpp b/libs/image/kis_distance_information.cpp
index ebed561bb1..a5fd8e87e2 100644
--- a/libs/image/kis_distance_information.cpp
+++ b/libs/image/kis_distance_information.cpp
@@ -1,328 +1,333 @@
 /*
  *  Copyright (c) 2010 Cyrille Berger <cberger@cberger.net>
  *  Copyright (c) 2013 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include <kis_distance_information.h>
 #include <brushengine/kis_paint_information.h>
 #include "kis_debug.h"
 #include <QtCore/qmath.h>
 #include <QVector2D>
 #include <QTransform>
 #include "kis_algebra_2d.h"
 
 #include "kis_lod_transform.h"
 
+const qreal MIN_DISTANCE_SPACING = 0.5;
+
+// Largest allowed interval when timed spacing is enabled, in milliseconds.
+const qreal MAX_TIMED_INTERVAL = 1000.0;
 
 struct Q_DECL_HIDDEN KisDistanceInformation::Private {
     Private() :
         accumDistance(),
         accumTime(0.0),
         lastDabInfoValid(false),
         lastPaintInfoValid(false),
         lockedDrawingAngle(0.0),
         hasLockedDrawingAngle(false),
         totalDistance(0.0) {}
 
     QPointF accumDistance;
     qreal accumTime;
     KisSpacingInformation spacing;
     QPointF lastPosition;
     qreal lastTime;
     bool lastDabInfoValid;
 
     KisPaintInformation lastPaintInformation;
     qreal lastAngle;
     bool lastPaintInfoValid;
 
     qreal lockedDrawingAngle;
     bool hasLockedDrawingAngle;
     qreal totalDistance;
 };
 
 KisDistanceInformation::KisDistanceInformation()
     : m_d(new Private)
 {
 }
 
 KisDistanceInformation::KisDistanceInformation(const QPointF &lastPosition,
                                                qreal lastTime)
     : m_d(new Private)
 {
     m_d->lastPosition = lastPosition;
     m_d->lastTime = lastTime;
 
     m_d->lastDabInfoValid = true;
 }
 
 KisDistanceInformation::KisDistanceInformation(const KisDistanceInformation &rhs)
     : m_d(new Private(*rhs.m_d))
 {
 
 }
 
 KisDistanceInformation::KisDistanceInformation(const KisDistanceInformation &rhs, int levelOfDetail)
     : m_d(new Private(*rhs.m_d))
 {
     KIS_ASSERT_RECOVER_NOOP(!m_d->lastPaintInfoValid &&
                             "The distance information "
                             "should be cloned before the "
                             "actual painting is started");
 
     KisLodTransform t(levelOfDetail);
     m_d->lastPosition = t.map(m_d->lastPosition);
 }
 
 KisDistanceInformation& KisDistanceInformation::operator=(const KisDistanceInformation &rhs)
 {
     *m_d = *rhs.m_d;
     return *this;
 }
 
 void KisDistanceInformation::overrideLastValues(const QPointF &lastPosition, qreal lastTime)
 {
     m_d->lastPosition = lastPosition;
     m_d->lastTime = lastTime;
 
     m_d->lastDabInfoValid = true;
 }
 
 KisDistanceInformation::~KisDistanceInformation()
 {
     delete m_d;
 }
 
 const KisSpacingInformation& KisDistanceInformation::currentSpacing() const
 {
     return m_d->spacing;
 }
 
 bool KisDistanceInformation::hasLastDabInformation() const
 {
     return m_d->lastDabInfoValid;
 }
 
 QPointF KisDistanceInformation::lastPosition() const
 {
     return m_d->lastPosition;
 }
 
 qreal KisDistanceInformation::lastTime() const
 {
     return m_d->lastTime;
 }
 
 qreal KisDistanceInformation::lastDrawingAngle() const
 {
     return m_d->lastAngle;
 }
 
 bool KisDistanceInformation::hasLastPaintInformation() const
 {
     return m_d->lastPaintInfoValid;
 }
 
 const KisPaintInformation& KisDistanceInformation::lastPaintInformation() const
 {
     return m_d->lastPaintInformation;
 }
 
 bool KisDistanceInformation::isStarted() const
 {
     return m_d->lastPaintInfoValid;
 }
 
 void KisDistanceInformation::registerPaintedDab(const KisPaintInformation &info,
                                                 const KisSpacingInformation &spacing)
 {
     m_d->totalDistance += KisAlgebra2D::norm(info.pos() - m_d->lastPosition);
 
     m_d->lastAngle = info.drawingAngleSafe(*this);
     m_d->lastPaintInformation = info;
     m_d->lastPaintInfoValid = true;
 
     m_d->lastPosition = info.pos();
     m_d->lastTime = info.currentTime();
     m_d->lastDabInfoValid = true;
 
     m_d->spacing = spacing;
 }
 
 qreal KisDistanceInformation::getNextPointPosition(const QPointF &start,
                                                    const QPointF &end,
                                                    qreal startTime,
                                                    qreal endTime)
 {
     // Compute interpolation factor based on distance.
     qreal distanceFactor = -1.0;
     if (m_d->spacing.isDistanceSpacingEnabled()) {
         distanceFactor = m_d->spacing.isIsotropic() ?
             getNextPointPositionIsotropic(start, end) :
             getNextPointPositionAnisotropic(start, end);
     }
 
     // Compute interpolation factor based on time.
     qreal timeFactor = -1.0;
     if (m_d->spacing.isTimedSpacingEnabled()) {
         timeFactor = getNextPointPositionTimed(startTime, endTime);
     }
 
     // Return the distance-based or time-based factor, whichever is smallest.
     if (distanceFactor < 0.0) {
         return timeFactor;
     } else if (timeFactor < 0.0) {
         return distanceFactor;
     } else {
         return qMin(distanceFactor, timeFactor);
     }
 }
 
 qreal KisDistanceInformation::getNextPointPositionIsotropic(const QPointF &start,
                                                             const QPointF &end)
 {
     qreal distance = m_d->accumDistance.x();
-    qreal spacing = qMax(qreal(0.5), m_d->spacing.distanceSpacing().x());
+    qreal spacing = qMax(MIN_DISTANCE_SPACING, m_d->spacing.distanceSpacing().x());
 
     if (start == end) {
         return -1;
     }
 
     qreal dragVecLength = QVector2D(end - start).length();
     qreal nextPointDistance = spacing - distance;
 
     qreal t;
 
     if (nextPointDistance <= dragVecLength) {
         t = nextPointDistance / dragVecLength;
         resetAccumulators();
     } else {
         t = -1;
         m_d->accumDistance.rx() += dragVecLength;
     }
 
     return t;
 }
 
 qreal KisDistanceInformation::getNextPointPositionAnisotropic(const QPointF &start,
                                                               const QPointF &end)
 {
     if (start == end) {
         return -1;
     }
 
-    qreal a_rev = 1.0 / qMax(qreal(0.5), m_d->spacing.distanceSpacing().x());
-    qreal b_rev = 1.0 / qMax(qreal(0.5), m_d->spacing.distanceSpacing().y());
+    qreal a_rev = 1.0 / qMax(MIN_DISTANCE_SPACING, m_d->spacing.distanceSpacing().x());
+    qreal b_rev = 1.0 / qMax(MIN_DISTANCE_SPACING, m_d->spacing.distanceSpacing().y());
 
     qreal x = m_d->accumDistance.x();
     qreal y = m_d->accumDistance.y();
 
     static const qreal eps = 2e-3; // < 0.2 deg
 
     qreal currentRotation = m_d->spacing.rotation();
     if (m_d->spacing.coordinateSystemFlipped()) {
         currentRotation = 2 * M_PI - currentRotation;
     }
 
     QPointF diff = end - start;
 
     if (currentRotation > eps) {
         QTransform rot;
         // since the ellipse is symmetrical, the sign
         // of rotation doesn't matter
         rot.rotateRadians(currentRotation);
         diff = rot.map(diff);
     }
 
     qreal dx = qAbs(diff.x());
     qreal dy = qAbs(diff.y());
 
     qreal alpha = pow2(dx * a_rev) + pow2(dy * b_rev);
     qreal beta = x * dx * a_rev * a_rev + y * dy * b_rev * b_rev;
     qreal gamma = pow2(x * a_rev) + pow2(y * b_rev) - 1;
 
     qreal D_4 = pow2(beta) - alpha * gamma;
 
     qreal t = -1.0;
 
     if (D_4 >= 0) {
         qreal k = (-beta + qSqrt(D_4)) / alpha;
 
         if (k >= 0.0 && k <= 1.0) {
             t = k;
             resetAccumulators();
         } else {
             m_d->accumDistance += KisAlgebra2D::abs(diff);
         }
     } else {
         warnKrita << "BUG: No solution for elliptical spacing equation has been found. This shouldn't have happened.";
     }
 
     return t;
 }
 
 qreal KisDistanceInformation::getNextPointPositionTimed(qreal startTime,
                                                         qreal endTime)
 {
     // If start time is not before end time, do not interpolate.
     if (!(startTime < endTime)) {
         return -1.0;
     }
     
-    qreal nextPointInterval = m_d->spacing.timedSpacingInterval() - m_d->accumTime;
+    qreal timedSpacingInterval = qMin(MAX_TIMED_INTERVAL, m_d->spacing.timedSpacingInterval());
+    qreal nextPointInterval = timedSpacingInterval - m_d->accumTime;
     
     // Note: nextPointInterval SHOULD always be positive, but I wasn't sure if floating point
     // roundoff error might make it nonpositive in some cases, so I included this check.
     if (nextPointInterval <= 0.0) {
         resetAccumulators();
         return 0.0;
     }
     else if (nextPointInterval <= endTime - startTime) {
         resetAccumulators();
         return nextPointInterval / (endTime - startTime);
     }
     else {
         m_d->accumTime += endTime - startTime;
         return -1.0;
     }
 }
 
 void KisDistanceInformation::resetAccumulators()
 {
     m_d->accumDistance = QPointF();
     m_d->accumTime = 0.0;
 }
 
 bool KisDistanceInformation::hasLockedDrawingAngle() const
 {
     return m_d->hasLockedDrawingAngle;
 }
 
 qreal KisDistanceInformation::lockedDrawingAngle() const
 {
     return m_d->lockedDrawingAngle;
 }
 
 void KisDistanceInformation::setLockedDrawingAngle(qreal angle)
 {
     m_d->hasLockedDrawingAngle = true;
     m_d->lockedDrawingAngle = angle;
 }
 
 qreal KisDistanceInformation::scalarDistanceApprox() const
 {
     return m_d->totalDistance;
 }
diff --git a/plugins/paintops/libpaintop/kis_airbrush_option.cpp b/plugins/paintops/libpaintop/kis_airbrush_option.cpp
index 4062df68da..ada31463ed 100644
--- a/plugins/paintops/libpaintop/kis_airbrush_option.cpp
+++ b/plugins/paintops/libpaintop/kis_airbrush_option.cpp
@@ -1,84 +1,84 @@
 /*
  *  Copyright (c) 2008 Boudewijn Rempt <boud@valdyas.org>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 #include "kis_airbrush_option.h"
 #include "kis_paintop_settings.h"
 #include <klocalizedstring.h>
 
 #include <QWidget>
 #include <QRadioButton>
 
 #include "ui_wdgairbrush.h"
 
-const qreal MINIMUM_RATE = 0.0;
+const qreal MINIMUM_RATE = 1.0;
 const qreal MAXIMUM_RATE = 1000.0;
 const int RATE_NUM_DECIMALS = 2;
-const qreal RATE_EXPONENT_RATIO = 3.0;
+const qreal RATE_EXPONENT_RATIO = 1.0;
 const qreal RATE_SINGLE_STEP = 1.0;
 const qreal DEFAULT_RATE = 20.0;
 
 class KisAirbrushWidget: public QWidget, public Ui::WdgAirbrush
 {
 public:
     KisAirbrushWidget(QWidget *parent = 0, bool canIgnoreSpacing = true)
         : QWidget(parent) {
         setupUi(this);
 
         sliderRate->setRange(MINIMUM_RATE, MAXIMUM_RATE, RATE_NUM_DECIMALS);
         sliderRate->setExponentRatio(RATE_EXPONENT_RATIO);
         sliderRate->setSingleStep(RATE_SINGLE_STEP);
         sliderRate->setValue(DEFAULT_RATE);
 
         checkBoxIgnoreSpacing->setVisible(canIgnoreSpacing);
         checkBoxIgnoreSpacing->setEnabled(canIgnoreSpacing);
     }
 };
 
 
 KisAirbrushOption::KisAirbrushOption(bool enabled, bool canIgnoreSpacing)
     : KisPaintOpOption(KisPaintOpOption::COLOR, enabled)
 {
     setObjectName("KisAirBrushOption");
     m_checkable = true;
     m_optionWidget = new KisAirbrushWidget(nullptr, canIgnoreSpacing);
     connect(m_optionWidget->sliderRate, SIGNAL(valueChanged(qreal)), SLOT(emitSettingChanged()));
     connect(m_optionWidget->checkBoxIgnoreSpacing, SIGNAL(toggled(bool)),
             SLOT(emitSettingChanged()));
     setConfigurationPage(m_optionWidget);
 }
 
 
 KisAirbrushOption::~KisAirbrushOption()
 {
 }
 
 void KisAirbrushOption::writeOptionSetting(KisPropertiesConfigurationSP setting) const
 {
     setting->setProperty(AIRBRUSH_ENABLED, isChecked());
     setting->setProperty(AIRBRUSH_RATE, m_optionWidget->sliderRate->value());
     setting->setProperty(AIRBRUSH_IGNORE_SPACING,
                          m_optionWidget->checkBoxIgnoreSpacing->isChecked());
 }
 
 void KisAirbrushOption::readOptionSetting(const KisPropertiesConfigurationSP setting)
 {
     setChecked(setting->getBool(AIRBRUSH_ENABLED));
     m_optionWidget->sliderRate->setValue(setting->getDouble(AIRBRUSH_RATE, DEFAULT_RATE));
     m_optionWidget->checkBoxIgnoreSpacing->setChecked(setting->getBool(AIRBRUSH_IGNORE_SPACING,
                                                                        false));
 }