<p>Yes, of course it does. The same amount of light is being spread across a wider area, so there's less light per area. Once you're past a few 10's of filament diameters, a point source is a highly accurate representation of most light bulbs. Even more so when there's a lens setup that causes the light to go through a point focus.</p>

CC BY-SA 3.0
2017-06-29T23:20:30.783Z
Thanks, I just wasn't sure if projection software for stereolithographic printers was set up in a way that compensated for this falloff by boosting power.
DMrFrost
CC BY-SA 3.0
2017-06-29T22:36:43.177Z
2017-06-29T22:36:43.177Z
Ecnerwal
<p>I was adjusting the position of our projector to allow for bigger prints to be generated.  I encountered a problem that at larger distances, our prints are not seeming to adhere as desired.  </p>

<p>Does the inverse square law of light apply to DLP projectors?  </p>

<p>I am aware that the inverse-square law only is 100% applicable when you have a point as your light source.  But I assume close to the same holds constant for other real world light sources.  </p>

<p>Unless DLP projectors compensate for distance with their power output. Is this the case?</p>

<hr>

<p>Cross-Post: @ <a href="https://physics.stackexchange.com/questions/342153/inverse-square-law-and-how-it-applies-to-projectors">Physics.SE</a></p>

CC BY-SA 3.0
2017-06-29T21:32:01.937Z
I am currently troubleshooting this.  Running a print right now with the law applied.  So far it seems much more solidly adhered.
DMrFrost
CC BY-SA 3.0
2017-06-29T22:15:24.923Z
I got pretty decent adhesion with a longer layer times.  Im guessing that this is indeed the case.
DMrFrost
CC BY-SA 3.0
2017-06-30T08:16:40.790Z
I'm voting to close this question as off-topic because it has been [cross-posted at physics.SE](https://physics.stackexchange.com/questions/342153/inverse-square-law-and-how-it-applies-to-projectors) and is probably more suitable there.
Tom van der Zanden
CC BY-SA 3.0
2017-07-02T18:16:48.073Z
While this question would probably be *quickly* answered over at Physics.SE, I believe the content is best suited for 3DPrinting.SE. @TomvanderZanden we need to broaden our spectrum of questions regarding other 3D Printer types and draw in more experts. Our site currently has a strong hold on FDM printing to accommodate advanced questions, but I don't feel that we're there yet in other 3D printing types. So, I'm leaving this question open in hopes to encourage more questions about DLP printers.
tbm0115
CC BY-SA 3.0
2017-07-02T19:32:51.440Z
@tbm0115 This question has already been cross-posted (verbatim) on Physics.SE and gotten good answers here. Having the same question exist on two different SE's is not good. [See here for a meta discussion](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-qu). This question could possibly be salvaged by turning it into a more 3D printing specific question. However, allowing substandard questions in a hope to attract more experts is counterproductive. Experts are attracted by interesting, high-quality questions.
Tom van der Zanden
<print-quality><sla>
Does the Inverse-Square law apply with SLA Printing?
DMrFrost
# Does the Inverse-Square law apply with SLA Printing?

(Asked by: username_0 on 2017-06-29)

I was adjusting the position of our projector to allow for bigger prints to be generated. I encountered a problem that at larger distances, our prints are not seeming to adhere as desired.

Does the inverse square law of light apply to DLP projectors?

I am aware that the inverse-square law only is 100% applicable when you have a point as your light source. But I assume close to the same holds constant for other real world light sources.

Unless DLP projectors compensate for distance with their power output. Is this the case?

---

Cross-Post: @ [Physics.SE](https://physics.stackexchange.com/questions/342153/inverse-square-law-and-how-it-applies-to-projectors)

**Tags:** print-quality, sla
> **Comments:**
> **username_0**: I am currently troubleshooting this.  Running a print right now with the law applied.  So far it seems much more solidly adhered.  
> **username_0**: I got pretty decent adhesion with a longer layer times.  Im guessing that this is indeed the case.  
> **username_1**: I'm voting to close this question as off-topic because it has been [cross-posted at physics.SE](https://physics.stackexchange.com/questions/342153/inverse-square-law-and-how-it-applies-to-projectors) and is probably more suitable there.  
> **username_2**: While this question would probably be *quickly* answered over at Physics.SE, I believe the content is best suited for 3DPrinting.SE. @TomvanderZanden we need to broaden our spectrum of questions regarding other 3D Printer types and draw in more experts. Our site currently has a strong hold on FDM printing to accommodate advanced questions, but I don't feel that we're there yet in other 3D printing types. So, I'm leaving this question open in hopes to encourage more questions about DLP printers.  
> **username_1**: @tbm0115 This question has already been cross-posted (verbatim) on Physics.SE and gotten good answers here. Having the same question exist on two different SE's is not good. [See here for a meta discussion](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-qu). This question could possibly be salvaged by turning it into a more 3D printing specific question. However, allowing substandard questions in a hope to attract more experts is counterproductive. Experts are attracted by interesting, high-quality questions.  

---

## 1 answers

### Answer by username_3 on 2017-06-29. Score: 4 | Accepted answer

Yes, of course it does. The same amount of light is being spread across a wider area, so there's less light per area. Once you're past a few 10's of filament diameters, a point source is a highly accurate representation of most light bulbs. Even more so when there's a lens setup that causes the light to go through a point focus.

> **Comments:**
> **username_0**: Thanks, I just wasn't sure if projection software for stereolithographic printers was set up in a way that compensated for this falloff by boosting power.  

---

