# No specular when using caustics **URL:** \ **Category:** General\ **Created:** [November 10, 2021, 4:45pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357 "2021-11-10T16:45:32Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Uniel](https://avatars.discourse-cdn.com/v4/letter/u/bbe5ce/32.png) [@Uniel](https://forums.chaos.com/u/Uniel)\ **Post date:** [November 10, 2021, 4:45pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/1 "2021-11-10T16:45:32Z")
Hi, I’m trying to render some stuff inside of a glass bottle with some water in it. I also want the render to show caustics. I’m using a physical sky and sun. I’m successfully getting caustics when turning Affect Shadows Off on the glass and water materials. I think this is the proper setup(?) (image 2). Problem is, I’m losing the specular on the objects inside of the bottle. I’ve made a simple scene to demonstrate this I’ve verified IRL that you in facts will see the reflection of the sun if an object is inside of a bottle (maybe it would be different if the object was actually inside of the glass medium). If I enable Affect Shadows I’ll get the specular back, but lose the caustics (image 3). I would like both specular _and_ caustics. Is this possible? Please have a look at the picture. Thank you. ![no_specular_when_using_caustics.jpg](https://europe1.discourse-cdn.com/chaosprd/original/2X/2/2c733f034dfd7e68bab5f4d710114e89402dd6a7.jpeg) ![no_specular_when_using_caustics.jpg](https://europe1.discourse-cdn.com/chaosprd/original/2X/2/2c733f034dfd7e68bab5f4d710114e89402dd6a7.jpeg) ---
**Author:** ![intercard](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/intercard/32/73175_2.png) [@intercard](https://forums.chaos.com/u/intercard)\ **Post date:** [November 10, 2021, 9:51pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/2 "2021-11-10T21:51:45Z")
Hello !! Humm I think it is a correct behavior .. maybe the bottle deflects the light rays modifying the specular ones inside. have you tried activating in the bottle material affect channels\> all channels from Refraction - advanced? ahh check the wrong shadow in your image 3, this is only my opinion, I am not a Chaos support technician!! regard and hugs !! ---
**Author:** ![Uniel](https://avatars.discourse-cdn.com/v4/letter/u/bbe5ce/32.png) [@Uniel](https://forums.chaos.com/u/Uniel)\ **Post date:** [November 11, 2021, 6:11am UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/3 "2021-11-11T06:11:31Z")
Hi Carlos @intercard , Thanks for your reply. Yes the shadows are wrong in image 3. In my mind the result should be like in image 2 but with the specular from image 1 and 3. Maybe this result is the correct behavior, but then it’s not mimicing the real world. I actually spent a good portion of yesterday putting real objects in a real glass bottle to check real world behavior. In the real world you don’t lose highlights from light sources just by putting the shiny object in a transparent bottle (that’s a fact, not an opinion btw). I tried changing the advanced setting to All Channels. It didn’t solve the issue. Thanks for the suggestion. 🙂 ---
**Author:** ![Uniel](https://avatars.discourse-cdn.com/v4/letter/u/bbe5ce/32.png) [@Uniel](https://forums.chaos.com/u/Uniel)\ **Post date:** [November 11, 2021, 6:26am UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/4 "2021-11-11T06:26:07Z")
This image pretty much illustrates what I’m looking for. I made a comp in Photoshop, where I put the specular back on the object inside the bottle. ![no_specular_when_using_caustics_02.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/0/6/065574783a90d12457232daad0d32d69a1885459.jpeg) ---
**Author:** ![hermit.crab](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/hermit.crab/32/46825_2.png) [@hermit.crab](https://forums.chaos.com/u/hermit.crab)\ **Post date:** [November 11, 2021, 3:50pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/5 "2021-11-11T15:50:10Z")
Is the bottle single-sided? If yes, does it help if you turn on the “Thin-walled” option? ---
**Author:** ![Uniel](https://avatars.discourse-cdn.com/v4/letter/u/bbe5ce/32.png) [@Uniel](https://forums.chaos.com/u/Uniel)\ **Post date:** [November 11, 2021, 4:43pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/6 "2021-11-11T16:43:05Z")
> [@hermit.crab](#): > > Is the bottle single-sided? If yes, does it help if you turn on the “Thin-walled” option? The bottle is built like a real bottle, with thickness, not single-sided, so no. ---
**Author:** ![hermit.crab](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/hermit.crab/32/46825_2.png) [@hermit.crab](https://forums.chaos.com/u/hermit.crab)\ **Post date:** [November 11, 2021, 5:03pm UTC](https://forums.chaos.com/t/no-specular-when-using-caustics/107357/7 "2021-11-11T17:03:47Z")
In that case,[send the scene](https://support.chaos.com/hc/en-us/requests/new) so we can take a look.