<function name="ChildrenSize" parent="Panel" type="classfunc"> <description>Returns the width and height of the space between the position of the panel (upper-left corner) and the max bound of the children panels (farthest reaching lower-right corner).</description> <realm>Client</realm> <rets> <ret name="" type="number">The children size width.</ret> <ret name="" type="number">The children size height.</ret> </rets> </function> <example> <description> Creates a recursively generated box of panels where the size of each panel is determined by the parent panel's children size + 10x10 pixels. Also they flash bluish colors, just for good measure. </description> <code> -- Parent panel BGPanel = vgui.Create("DPanel") BGPanel:SetSize(200, 200) BGPanel:Center() local panel, child_size_w, child_size_h = nil, 0, 0 -- Create increasingly large blocks until children size exceeds the size of the panel while(BGPanel:ChildrenSize() &amp;lt; BGPanel:GetSize()) do while(BGPanel:ChildrenSize() &lt; BGPanel:GetSize()) do child_w, child_h = BGPanel:ChildrenSize() panel = vgui.Create("DPanel", BGPanel) panel:SetPos(0, 0) -- Increase size based on the children size panel:SetSize(child_w+10, child_h+10) -- Random bluish color every frame function panel:PerformLayout() self:InvalidateLayout() -- Call this again next frame self:SetBackgroundColor(Color(math.random(0, 255), 255, math.random(0, 255))) end -- Move to back so we can see the effect panel:MoveToBack() end </code> <output><image src="Panel_ChildrenSize_example1.gif"/></output> </example>