Name the unusual feature
Instead of only writing nonstandard, explain whether you mean an arch, a sloping top, different heights or connected sections. A plain description is enough if the technical term is unknown. An overall photograph and section labels keep everyone discussing the same opening. Ask for the shape and intended use to be assessed together before prescribing a product type. Naming a shape does not establish system compatibility.
Prepare three levels of photographs
Provide an overall room view, the complete window and separate accessible details. Include the wall, ceiling, floor and nearby furniture in the wider view. Detail photographs can show the frame, handle and existing rail. Add simple A and B labels where needed. Keep personal documents and unnecessary private information out of the frame. The package should explain spatial relationships rather than hide awkward corners behind an attractive presentation.
Separate known information from unknowns
If you have an earlier plan or dimensions, explain when they were obtained and for what purpose. Distinguish approximate numbers from checked measurements. Leave unfamiliar angles, curves and high fixing areas explicitly unknown instead of filling gaps with guesses. An acknowledged unknown is more useful than false precision. Old curtain dimensions do not automatically transfer to a different system because a new heading or position can change the requirement.
Use a hypothetical arched example
Imagine a window with a straight lower section 120 cm wide and an arched top. The number is illustrative, not an ordering dimension. Show the arch in a photograph without trying to derive its curve yourself. Clarify whether you want to cover the entire arch or leave it visible. These are different objectives that may require different proposals. The example frames the question rather than confirming a suitable system.
Record use and existing obstacles
Mark opening sections, a passage door, radiator, air conditioner and nearby lighting. Explain which objects will remain and where daily access matters. Leave an unknown wall structure unknown: surface appearance does not determine a fixing solution. Preparation does not require moving heavy objects or reaching high areas. Record the limitation and identify that area for assessment during an agreed survey instead of attempting to resolve it yourself.
Explain your reference and its limits
State exactly what appeals to you in the reference: gathered shape, visible frame, colour or number of layers. Do not assume a solution in another home can be reproduced on your arch or slope. Say whether alternative appearances are welcome. List privacy, daylight and care separately. A picture does not establish composition, fixings or blackout performance; those details need clarification for the particular proposal and actual site conditions.
Plan for confirmation after the survey
Describe these details in the enquiry form and prepare photographs for the agreed visit. When agreeing timing and access, identify areas needing special attention. The next step is written clarification of finished dimensions, system and scope after the site assessment. Initial sketches and approximate numbers should not become final order confirmation. If a parameter remains unclear, keep it as an open question even after the fabric colour has been selected.