How to model an accurate parabolic mirror with a known focal point?












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I am new to Blender and really enjoying it now, but... I want to make an accurate parabolic mirror with a known focal point. For example, I would want to have it focussed so that a parallel beam could be reflected from the focal point outwards.



This will be 3d printed and then used with a tiny sonic transmitter/receiver set up to map surroundings, for a small rover bot. I think this could be done with a Bezier Curve, at least the general shape could be emulated. But how to make the parabular accurate for the focal point? I am guessing that once the general shape was made, it could be extruded away from the front to make it more solid.



The focal point needs to known so I can add struts to mount the sonic electronics. I'm not worried about scale or size at this point, just the method that I can repeat. Ive looked for some scripts that might help, but not found anything yet.



Thanks for your help.










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    8












    $begingroup$


    I am new to Blender and really enjoying it now, but... I want to make an accurate parabolic mirror with a known focal point. For example, I would want to have it focussed so that a parallel beam could be reflected from the focal point outwards.



    This will be 3d printed and then used with a tiny sonic transmitter/receiver set up to map surroundings, for a small rover bot. I think this could be done with a Bezier Curve, at least the general shape could be emulated. But how to make the parabular accurate for the focal point? I am guessing that once the general shape was made, it could be extruded away from the front to make it more solid.



    The focal point needs to known so I can add struts to mount the sonic electronics. I'm not worried about scale or size at this point, just the method that I can repeat. Ive looked for some scripts that might help, but not found anything yet.



    Thanks for your help.










    share|improve this question









    $endgroup$















      8












      8








      8


      3



      $begingroup$


      I am new to Blender and really enjoying it now, but... I want to make an accurate parabolic mirror with a known focal point. For example, I would want to have it focussed so that a parallel beam could be reflected from the focal point outwards.



      This will be 3d printed and then used with a tiny sonic transmitter/receiver set up to map surroundings, for a small rover bot. I think this could be done with a Bezier Curve, at least the general shape could be emulated. But how to make the parabular accurate for the focal point? I am guessing that once the general shape was made, it could be extruded away from the front to make it more solid.



      The focal point needs to known so I can add struts to mount the sonic electronics. I'm not worried about scale or size at this point, just the method that I can repeat. Ive looked for some scripts that might help, but not found anything yet.



      Thanks for your help.










      share|improve this question









      $endgroup$




      I am new to Blender and really enjoying it now, but... I want to make an accurate parabolic mirror with a known focal point. For example, I would want to have it focussed so that a parallel beam could be reflected from the focal point outwards.



      This will be 3d printed and then used with a tiny sonic transmitter/receiver set up to map surroundings, for a small rover bot. I think this could be done with a Bezier Curve, at least the general shape could be emulated. But how to make the parabular accurate for the focal point? I am guessing that once the general shape was made, it could be extruded away from the front to make it more solid.



      The focal point needs to known so I can add struts to mount the sonic electronics. I'm not worried about scale or size at this point, just the method that I can repeat. Ive looked for some scripts that might help, but not found anything yet.



      Thanks for your help.







      add-on bezier






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      asked Jan 18 at 9:27









      Andrea RichardsAndrea Richards

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          1 Answer
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          11












          $begingroup$

          Add mesh z surface



          Enable the add mesh extra objects addon, then from add menu choose add > mesh > math function > math z surface



          The equation of a paraboloid with focus f is



          (x ** 2 + y ** 2) / (4 * f)


          enter image description hereparaboloid with focus at (0, 0, 1)




          • Thickness can be added with the solidify modifier.






          share|improve this answer











          $endgroup$













          • $begingroup$
            I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
            $endgroup$
            – Andrea Richards
            Jan 18 at 13:44











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          11












          $begingroup$

          Add mesh z surface



          Enable the add mesh extra objects addon, then from add menu choose add > mesh > math function > math z surface



          The equation of a paraboloid with focus f is



          (x ** 2 + y ** 2) / (4 * f)


          enter image description hereparaboloid with focus at (0, 0, 1)




          • Thickness can be added with the solidify modifier.






          share|improve this answer











          $endgroup$













          • $begingroup$
            I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
            $endgroup$
            – Andrea Richards
            Jan 18 at 13:44
















          11












          $begingroup$

          Add mesh z surface



          Enable the add mesh extra objects addon, then from add menu choose add > mesh > math function > math z surface



          The equation of a paraboloid with focus f is



          (x ** 2 + y ** 2) / (4 * f)


          enter image description hereparaboloid with focus at (0, 0, 1)




          • Thickness can be added with the solidify modifier.






          share|improve this answer











          $endgroup$













          • $begingroup$
            I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
            $endgroup$
            – Andrea Richards
            Jan 18 at 13:44














          11












          11








          11





          $begingroup$

          Add mesh z surface



          Enable the add mesh extra objects addon, then from add menu choose add > mesh > math function > math z surface



          The equation of a paraboloid with focus f is



          (x ** 2 + y ** 2) / (4 * f)


          enter image description hereparaboloid with focus at (0, 0, 1)




          • Thickness can be added with the solidify modifier.






          share|improve this answer











          $endgroup$



          Add mesh z surface



          Enable the add mesh extra objects addon, then from add menu choose add > mesh > math function > math z surface



          The equation of a paraboloid with focus f is



          (x ** 2 + y ** 2) / (4 * f)


          enter image description hereparaboloid with focus at (0, 0, 1)




          • Thickness can be added with the solidify modifier.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Jan 18 at 14:16

























          answered Jan 18 at 10:32









          batFINGERbatFINGER

          23.9k42673




          23.9k42673












          • $begingroup$
            I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
            $endgroup$
            – Andrea Richards
            Jan 18 at 13:44


















          • $begingroup$
            I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
            $endgroup$
            – Andrea Richards
            Jan 18 at 13:44
















          $begingroup$
          I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
          $endgroup$
          – Andrea Richards
          Jan 18 at 13:44




          $begingroup$
          I've learnt a number of things about Blender from your answer. I didn't realise that it could be so easy if you know what you are doing. Thanks so much!
          $endgroup$
          – Andrea Richards
          Jan 18 at 13:44


















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