Index: binaries/data/mods/public/gui/common/tooltips.js
===================================================================
--- binaries/data/mods/public/gui/common/tooltips.js
+++ binaries/data/mods/public/gui/common/tooltips.js
@@ -207,7 +207,7 @@
 function armorLevelToPercentageString(level)
 {
 	return sprintf(translate("%(percentage)s%%"), {
-		"percentage": (100 - Math.round(Math.pow(0.9, level) * 100))
+		"percentage": level == "Infinity" ? 100 : (100 - Math.round(Math.pow(0.9, level) * 100))
 	});
 }
 
@@ -221,7 +221,7 @@
 		"details":
 			Object.keys(template.armour).map(
 				dmgType => sprintf(translate("%(damage)s %(damageType)s %(armorPercentage)s"), {
-					"damage": template.armour[dmgType].toFixed(1),
+					"damage": template.armour[dmgType] == "Infinity" ? "∞" : template.armour[dmgType].toFixed(1),
 					"damageType": unitFont(translateWithContext("damage type", g_DamageTypes.GetNames()[dmgType])),
 					"armorPercentage":
 						'[font="sans-10"]' +
Index: binaries/data/mods/public/simulation/components/Armour.js
===================================================================
--- binaries/data/mods/public/simulation/components/Armour.js
+++ binaries/data/mods/public/simulation/components/Armour.js
@@ -34,46 +34,52 @@
 
 /**
  * Take damage according to the entity's armor.
- * @param {Object} strengths - { "hack": number, "pierce": number, "crush": number } or something like that.
+ * @param {Object} attackStrengths - { "hack": number, "pierce": number, "crush": number } or something like that.
  * @param {number} multiplier - the damage multiplier.
  * Returns object of the form { "killed": false, "change": -12 }.
  */
-Armour.prototype.TakeDamage = function(strengths, multiplier = 1)
+Armour.prototype.TakeDamage = function(attackStrengths, multiplier = 1)
 {
 	if (this.invulnerable)
 		return { "killed": false, "change": 0 };
 
 	// Adjust damage values based on armour; exponential armour: damage = attack * 0.9^armour
-	var armourStrengths = this.GetArmourStrengths();
+	let armourStrengths = this.GetArmourStrengths();
 
 	// Total is sum of individual damages
 	// Don't bother rounding, since HP is no longer integral.
-	var total = 0;
-	for (let type in strengths)
-		total += strengths[type] * multiplier * Math.pow(0.9, armourStrengths[type] || 0);
+	let total = 0;
+	for (let type in attackStrengths)
+	{
+		if (armourStrengths[type] == "Infinity")
+			continue;
+
+		total += attackStrengths[type] * multiplier * Math.pow(0.9, armourStrengths[type] || 0);
+	}
 
 	// Reduce health
-	var cmpHealth = Engine.QueryInterface(this.entity, IID_Health);
+	let cmpHealth = Engine.QueryInterface(this.entity, IID_Health);
 	return cmpHealth.Reduce(total);
 };
 
 Armour.prototype.GetArmourStrengths = function()
 {
 	// Work out the armour values with technology effects
-	var applyMods = (type, foundation) => {
-		var strength;
+	let applyMods = (type, foundation) => {
+		let strength;
 		if (foundation)
 		{
-			strength = +this.template.Foundation[type];
+			strength = this.template.Foundation[type];
 			type = "Foundation/" + type;
 		}
 		else
-			strength = +this.template[type];
+			strength = this.template[type];
 
-		return ApplyValueModificationsToEntity("Armour/" + type, strength, this.entity);
+		return strength == "Infinity" ? "Infinity" :
+			ApplyValueModificationsToEntity("Armour/" + type, +strength, this.entity);
 	};
 
-	var foundation = Engine.QueryInterface(this.entity, IID_Foundation) && this.template.Foundation;
+	let foundation = Engine.QueryInterface(this.entity, IID_Foundation) && this.template.Foundation;
 
 	let ret = {};
 	for (let damageType of DamageTypes.GetTypes())
Index: binaries/data/mods/public/simulation/components/Attack.js
===================================================================
--- binaries/data/mods/public/simulation/components/Attack.js
+++ binaries/data/mods/public/simulation/components/Attack.js
@@ -315,6 +315,11 @@
 	// reach each other, no matter how close they come.
 	let heightDiff = Math.abs(cmpThisPosition.GetHeightOffset() - cmpTargetPosition.GetHeightOffset());
 
+	let armourStrengths;
+	let cmpTargetArmour = Engine.QueryInterface(target, IID_DamageReceiver);
+	if (cmpTargetArmour)
+		armourStrengths = cmpTargetArmour.GetArmourStrengths();
+
 	for (let type of types)
 	{
 		if (type != "Capture" && (!cmpEntityPlayer.IsEnemy(targetOwner) || !cmpHealth || !cmpHealth.GetHitpoints()))
@@ -326,6 +331,22 @@
 		if (heightDiff > this.GetRange(type).max)
 			continue;
 
+		if (type != "Capture")
+		{
+			let attackStrengths = this.GetAttackStrengths(type);
+			let canDamage = false;
+			for (let damageType in attackStrengths)
+			{
+				if (attackStrengths[damageType] != 0 && armourStrengths[damageType] != "Infinity")
+				{
+					canDamage = true;
+					break;
+				}
+			}
+			if (!canDamage)
+				return false;
+		}
+
 		let restrictedClasses = this.GetRestrictedClasses(type);
 		if (!restrictedClasses.length)
 			return true;
Index: binaries/data/mods/public/simulation/helpers/DamageTypes.js
===================================================================
--- binaries/data/mods/public/simulation/helpers/DamageTypes.js
+++ binaries/data/mods/public/simulation/helpers/DamageTypes.js
@@ -1,7 +1,7 @@
 DamageTypes.prototype.BuildSchema = function(helptext = "")
 {
 	return "<interleave>" + this.GetTypes().reduce((schema, type) =>
-		schema + "<element name='"+type+"' a:help='"+type+" "+helptext+"'><ref name='nonNegativeDecimal'/></element>",
+		schema + "<element name='"+type+"' a:help='"+type+" "+helptext+"'><choice><ref name='nonNegativeDecimal'/><value>Infinity</value></choice></element>",
 	"") + "</interleave>";
 };