Problem with a replacement transformation

[arnaudflavier]

Hi everyone ! i'm a beginner on manim.

I'm having trouble entering my code. The aim is to train myself, so I'm trying to give a little "demonstration" of a formula using animations. However, at the "ReplacementTransform(x,f)" step, the text x does the transformation animation but remains present, as if it were duplicated. I've managed to find a few discussions from people who've encountered this difficulty with an object but not with text, so I can't see what I'm missing in this step. Why does the text stay in place? Enclosed is my code. Thank you in advance.

from manim import *

class demo1(Scene):
    def construct(self):

        t = Text("Sackur Tetrode relation")

        self.play(Write(t),run_time=2)
        self.wait(1)

        z = Text("not a complete demo. Just a way to find the relation",font_size=28,color=RED)

        self.play(ReplacementTransform(t, z))
        self.wait(3)
        self.play(Unwrite(z),run_time=1)


        #s = MathTex("S = NkT^2 \left( \frac{\partial q}{\partial T} \right)_{V}")
        s = MathTex(r"S = NkT^2 \left( \frac{\partial q}{\partial T} \right)_{V}")

        self.play(Write(s),run_time=2)
        self.wait(2)
        self.play(s.animate.to_edge(UP))

        q = MathTex(r"q = q_{trans} \frac{e}{N}")
        n = MathTex(r"q_{trans} = \frac{V}{\Lambda^{3}}")
        l = MathTex (r"q = \frac{Ve}{\Lambda^{3}N}")
        x = MathTex(r"ln(q) = ln(Ve)-ln({\Lambda^3)-ln(N)}")
        f = MathTex (r"ln(q) = ln(Ve)- 3ln({\Lambda)-ln(N)}")
        a = MathTex(r"\Lambda = \frac{h}{\sqrt{2\pi mkT}}")


        self.play(Write(q),run_time=2)
        self.wait(2)
        self.play(q.animate.to_edge(LEFT))
        self.play(Write(n),run_time=2)
        self.wait(2)
        self.play(ReplacementTransform(q,l),ReplacementTransform(n,l))
        self.wait(1)
        self.play(ReplacementTransform(l,x))
        self.wait(2)
        self.play(ReplacementTransform(x,f))


        self.wait(1)
        self.play(f.animate.move_to([0,1.5,0]))
        #self.play(Write(a),run_time=2)

[behackl]

When you play the two animations

self.play(ReplacementTransform(q,l),ReplacementTransform(n,l))

something odd happens that I'm not entirely sure I can fully explain. My best guess without investigating further is that the formula you store in l somehow gets added to the scene twice. To avoid this sort of issue, you can group the two source mobjects together first and then transform the group, like this:

self.play(ReplacementTransform(VGroup(q, n), l))

[arnaudflavier]

Thank you so much... This effectively creates the "l" scene twice, rather than grouping the two transitions into one. The two formulas should therefore be grouped into a single transition... Thank you very much. It works perfectly now !